Dissertations / Theses on the topic 'Lamb (Meat)'

The purpose of this research was to evaluate the effects of saponins on lamb meat quality. In the first experiment, increasing levels of saponins from Quillaja saponaria L. were supplemented to lambs to evaluate their effects on fatty acid composition and cholesterol content in the muscle longissimus dorsi. In the second experiment, saponin supplementation was given as a single ration or as a choice with tannin to evaluate its effect on lamb meat quality. The lower and higher concentration of C14:1cis-9 in the lamb meat, respectively in the first and the second experiments, suggest a possible effect of these PSCs on delta9-desaturase enzyme activity. Moreover, the low concentartion of furan,2-pentyl and TBARS values in the meat of lamb fed saponin diet suggest an antioxidant effect of saponin against lipid oxidation. Further investigations are necessary to assess the specific role of saponins on meat quality.

The lamb industry is actively seeking to improve the quality of lamb meat produced in Australia. Ultimate pH (pHu) is a key determinant of red meat eating quality although this measurement has not been adopted formally by the Australian lamb meat industry. Muscle glycogen concentration is a major determinant of pHu in red meat. This thesis investigates glycogen concentration in lamb muscle and the ultimate pH (pHu) of lamb meat under commercial industry conditions as well as exploring by experimentation, some of the factors that control muscle glycogen concentration in lamb muscle. The results of this work has contributed to an understanding of the significance of high pHu meat to the lamb industry and will assist with developing new management strategies for lambs that avoid low muscle glycogen concentration at the point of slaughter, thus high pHu in meat derived from lambs. The first part of the study (Experiments 1 and 2) undertook to determine the ranges of muscle glycogen concentration and lamb meat pHu found under commercial conditions and to measure any changes in these parameters associated with consignment of lambs from farm to abattoir and lairage at abattoirs. This study utilised a new biopsy technique that allowed muscle collection from lambs on farm. Some 16 different consignments of lambs and 3 consignments of lactating ewes were intensively monitored on farm and at abattoirs over a range of lairage times. Sensory evaluation tests were done using meat from 6 of these consignments. The results showed there to be considerable variation between lamb consignments with some consignments having a very high and other consignments having a very low incidence of meat with a high pHu. On balance “on farm” factors were concluded to have a greater impact on muscle glycogen concentration at slaughter than “post farm gate” factors. However, there was evidence that muscle glycogen concentrations decreased during the farm curfew and transport period for some consignments so both “on farm” and “post farm gate factors” can be important. Characteristically glycogen loss occurred during the farm curfew and transport period in consignments of Merino lambs that had high muscle glycogen concentrations prior to consignment. Holding lambs in lairage caused no negative effects on muscle glycogen concentration although there was some evidence that very short lairage periods may increase meat pHu without causing a change in muscle glycogen concentration. It was concluded from these experiments that the mean muscle glycogen concentration of a group of lambs needs to be greater than 1.5 g/100g on farm in order for the pHu of lamb meat to be less than 5.7. Subsequent to this industry study, an experiment (Experiment 3) was done to gain an understanding of muscle glycogen concentration as being an integral part of whole body glucose metabolism. This experiment investigated the effects of exercise on a range of different muscles and tissues of lambs including liver, kidney, skin and gastrointestinal tract. Interactions between glycogen concentrations in the liver and muscle with time after exercise showed that glycogen repletion occurred in the liver before muscle tissue. This effect was a unique finding and could explain in part the slow rate of glycogen repletion in muscle tissue that is characteristic for ruminants. Another major finding was an accumulation of glycogen concentration in skin during the recovery period after exercise. It was postulated that this effect may be due to the supply of glucose to glycolytic tissues being continued even when demand for glucose in the skin was low and the capacity to store glycogen in muscle was very high. Experiment 3 confirmed the existence of a relationship between metabolisable energy (ME) intake and glycogen repletion in muscle tissues and found a slightly different relationship between ME intake and glycogen repletion in the liver tissue of lambs. Muscle glycogen concentration did not change in fasted lambs and the rate of glycogen repletion in muscle after exercise was dependent on ME intake. Differences were observed between different muscles, particularly between M. longissimus thoracis et lumborum (LTL) and all other muscles, in relation to the change in glycogen concentration with time after exercise. Glycogen concentrations changed less rapidly in the LTL than other muscles. Glycogen concentration in the liver was associated negatively with time after exercise in fasted lambs and positively with time after exercise in fed lambs. Several experiments (Experiments 4, 5 and 6) were conducted to determine the affects of different nutritional factors on muscle glycogen concentration in lambs, both on farm and after commercial slaughter. These studies showed that short term increases in ME intake will increase muscle glycogen concentration to a maximum level over a period of about 7 days (Experiment 4). Diet composition did not affect the change in muscle glycogen concentration associated with an increase in ME intake although results from this experiment (Experiment 5) were not entirely conclusive. There was evidence that the type of feeding and finishing system may influence the susceptibility of muscle glycogen concentration to change during consignment of lambs to slaughter. Results from these experiments demonstrated that a goal for muscle glycogen concentration in lambs on farm of 1.5g/100g is quite achievable with contemporaneous management systems. Finally this study highlighted the need for further research in a number of key areas in order that muscle glycogen concentration in lambs to be fully understood. In particular, the role of muscle glycogen turnover in relation to muscle glycogen concentration was noted as an area for which further research is warranted.

The lamb industry is actively seeking to improve the quality of lamb meat produced in Australia. Ultimate pH (pHu) is a key determinant of red meat eating quality although this measurement has not been adopted formally by the Australian lamb meat industry. Muscle glycogen concentration is a major determinant of pHu in red meat. This thesis investigates glycogen concentration in lamb muscle and the ultimate pH (pHu) of lamb meat under commercial industry conditions as well as exploring by experimentation, some of the factors that control muscle glycogen concentration in lamb muscle. The results of this work has contributed to an understanding of the significance of high pHu meat to the lamb industry and will assist with developing new management strategies for lambs that avoid low muscle glycogen concentration at the point of slaughter, thus high pHu in meat derived from lambs. The first part of the study (Experiments 1 and 2) undertook to determine the ranges of muscle glycogen concentration and lamb meat pHu found under commercial conditions and to measure any changes in these parameters associated with consignment of lambs from farm to abattoir and lairage at abattoirs. This study utilised a new biopsy technique that allowed muscle collection from lambs on farm. Some 16 different consignments of lambs and 3 consignments of lactating ewes were intensively monitored on farm and at abattoirs over a range of lairage times. Sensory evaluation tests were done using meat from 6 of these consignments. The results showed there to be considerable variation between lamb consignments with some consignments having a very high and other consignments having a very low incidence of meat with a high pHu. On balance 'on farm' factors were concluded to have a greater impact on muscle glycogen concentration at slaughter than 'post farm gate' factors. However, there was evidence that muscle glycogen concentrations decreased during the farm curfew and transport period for some consignments so both 'on farm' and 'post farm gate factors' can be important. Characteristically glycogen loss occurred during the farm curfew and transport period in consignments of Merino lambs that had high muscle glycogen concentrations prior to consignment. Holding lambs in lairage caused no negative effects on muscle glycogen concentration although there was some evidence that very short lairage periods may increase meat pHu without causing a change in muscle glycogen concentration. It was concluded from these experiments that the mean muscle glycogen concentration of a group of lambs needs to be greater than 1.5 g/100g on farm in order for the pHu of lamb meat to be less than 5.7. Subsequent to this industry study, an experiment (Experiment 3) was done to gain an understanding of muscle glycogen concentration as being an integral part of whole body glucose metabolism. This experiment investigated the effects of exercise on a range of different muscles and tissues of lambs including liver, kidney, skin and gastrointestinal tract. Interactions between glycogen concentrations in the liver and muscle with time after exercise showed that glycogen repletion occurred in the liver before muscle tissue. This effect was a unique finding and could explain in part the slow rate of glycogen repletion in muscle tissue that is characteristic for ruminants. Another major finding was an accumulation of glycogen concentration in skin during the recovery period after exercise. It was postulated that this effect may be due to the supply of glucose to glycolytic tissues being continued even when demand for glucose in the skin was low and the capacity to store glycogen in muscle was very high. Experiment 3 confirmed the existence of a relationship between metabolisable energy (ME) intake and glycogen repletion in muscle tissues and found a slightly different relationship between ME intake and glycogen repletion in the liver tissue of lambs. Muscle glycogen concentration did not change in fasted lambs and the rate of glycogen repletion in muscle after exercise was dependent on ME intake. Differences were observed between different muscles, particularly between M. longissimus thoracis et lumborum (LTL) and all other muscles, in relation to the change in glycogen concentration with time after exercise. Glycogen concentrations changed less rapidly in the LTL than other muscles. Glycogen concentration in the liver was associated negatively with time after exercise in fasted lambs and positively with time after exercise in fed lambs. Several experiments (Experiments 4, 5 and 6) were conducted to determine the affects of different nutritional factors on muscle glycogen concentration in lambs, both on farm and after commercial slaughter. These studies showed that short term increases in ME intake will increase muscle glycogen concentration to a maximum level over a period of about 7 days (Experiment 4). Diet composition did not affect the change in muscle glycogen concentration associated with an increase in ME intake although results from this experiment (Experiment 5) were not entirely conclusive. There was evidence that the type of feeding and finishing system may influence the susceptibility of muscle glycogen concentration to change during consignment of lambs to slaughter. Results from these experiments demonstrated that a goal for muscle glycogen concentration in lambs on farm of 1.5g/100g is quite achievable with contemporaneous management systems. Finally this study highlighted the need for further research in a number of key areas in order that muscle glycogen concentration in lambs to be fully understood. In particular, the role of muscle glycogen turnover in relation to muscle glycogen concentration was noted as an area for which further research is warranted.

The lamb industry is actively seeking to improve the quality of lamb meat produced in Australia. Ultimate pH (pHu) is a key determinant of red meat eating quality although this measurement has not been adopted formally by the Australian lamb meat industry. Muscle glycogen concentration is a major determinant of pHu in red meat. This thesis investigates glycogen concentration in lamb muscle and the ultimate pH (pHu) of lamb meat under commercial industry conditions as well as exploring by experimentation, some of the factors that control muscle glycogen concentration in lamb muscle. The results of this work has contributed to an understanding of the significance of high pHu meat to the lamb industry and will assist with developing new management strategies for lambs that avoid low muscle glycogen concentration at the point of slaughter, thus high pHu in meat derived from lambs. The first part of the study (Experiments 1 and 2) undertook to determine the ranges of muscle glycogen concentration and lamb meat pHu found under commercial conditions and to measure any changes in these parameters associated with consignment of lambs from farm to abattoir and lairage at abattoirs. This study utilised a new biopsy technique that allowed muscle collection from lambs on farm. Some 16 different consignments of lambs and 3 consignments of lactating ewes were intensively monitored on farm and at abattoirs over a range of lairage times. Sensory evaluation tests were done using meat from 6 of these consignments. The results showed there to be considerable variation between lamb consignments with some consignments having a very high and other consignments having a very low incidence of meat with a high pHu. On balance 'on farm' factors were concluded to have a greater impact on muscle glycogen concentration at slaughter than 'post farm gate' factors. However, there was evidence that muscle glycogen concentrations decreased during the farm curfew and transport period for some consignments so both 'on farm' and 'post farm gate factors' can be important. Characteristically glycogen loss occurred during the farm curfew and transport period in consignments of Merino lambs that had high muscle glycogen concentrations prior to consignment. Holding lambs in lairage caused no negative effects on muscle glycogen concentration although there was some evidence that very short lairage periods may increase meat pHu without causing a change in muscle glycogen concentration. It was concluded from these experiments that the mean muscle glycogen concentration of a group of lambs needs to be greater than 1.5 g/100g on farm in order for the pHu of lamb meat to be less than 5.7. Subsequent to this industry study, an experiment (Experiment 3) was done to gain an understanding of muscle glycogen concentration as being an integral part of whole body glucose metabolism. This experiment investigated the effects of exercise on a range of different muscles and tissues of lambs including liver, kidney, skin and gastrointestinal tract. Interactions between glycogen concentrations in the liver and muscle with time after exercise showed that glycogen repletion occurred in the liver before muscle tissue. This effect was a unique finding and could explain in part the slow rate of glycogen repletion in muscle tissue that is characteristic for ruminants. Another major finding was an accumulation of glycogen concentration in skin during the recovery period after exercise. It was postulated that this effect may be due to the supply of glucose to glycolytic tissues being continued even when demand for glucose in the skin was low and the capacity to store glycogen in muscle was very high. Experiment 3 confirmed the existence of a relationship between metabolisable energy (ME) intake and glycogen repletion in muscle tissues and found a slightly different relationship between ME intake and glycogen repletion in the liver tissue of lambs. Muscle glycogen concentration did not change in fasted lambs and the rate of glycogen repletion in muscle after exercise was dependent on ME intake. Differences were observed between different muscles, particularly between M. longissimus thoracis et lumborum (LTL) and all other muscles, in relation to the change in glycogen concentration with time after exercise. Glycogen concentrations changed less rapidly in the LTL than other muscles. Glycogen concentration in the liver was associated negatively with time after exercise in fasted lambs and positively with time after exercise in fed lambs. Several experiments (Experiments 4, 5 and 6) were conducted to determine the affects of different nutritional factors on muscle glycogen concentration in lambs, both on farm and after commercial slaughter. These studies showed that short term increases in ME intake will increase muscle glycogen concentration to a maximum level over a period of about 7 days (Experiment 4). Diet composition did not affect the change in muscle glycogen concentration associated with an increase in ME intake although results from this experiment (Experiment 5) were not entirely conclusive. There was evidence that the type of feeding and finishing system may influence the susceptibility of muscle glycogen concentration to change during consignment of lambs to slaughter. Results from these experiments demonstrated that a goal for muscle glycogen concentration in lambs on farm of 1.5g/100g is quite achievable with contemporaneous management systems. Finally this study highlighted the need for further research in a number of key areas in order that muscle glycogen concentration in lambs to be fully understood. In particular, the role of muscle glycogen turnover in relation to muscle glycogen concentration was noted as an area for which further research is warranted.

Genetic selection to increase lamb growth is advantageous in reducing the time it takes for lambs to reach market weight. However the effects of rapid growth on muscle fibre type, as indicated by oxidative capacity, is not clear. Muscle fibre type is intrinsically linked with attributes of meat quality, which are becoming increasing important to consumers. Therefore, changes to muscle fibre type through selection for growth may impact meat quality. Producers can impact lamb growth at any time during the growth period including the weaning (100 days) and post weaning time points (150 days). As not all lambs were weighed at these time points a growth curve was fitted to the live weight data of each individual animal to allow weight to be estimated at any time point during the growth period. Once estimates of weight and growth rate at the weaning and post weaning time points were obtained, the impact of growth on muscle fibre type and meat quality traits could be investigated. In the first experiment growth curves were fitted to live weight data for 18,185 lambs with weight data between birth and 300 days. Linear (cubic polynomial), nonlinear (Brody) and random effects models were fitted and the characteristics of the residual values examined to determine the best curve fit. The random effects model was hypothesised to have the lowest residual values as it is based on a population, rather than an individual fit, and is less biased when fitting growth curves to weight recordings from animals with different durations of data collection. However, the cubic polynomial fit had the lowest average residual values and the Brody fit had the highest. The difference between the residual values for the fit of each function was relatively small therefore the decision on which function to use was based on a variety of additional factors. As it is a population based fit, a random effects model accommodates missing weight recordings and different durations of data collection, which are common with industry data recording, without biasing the fit. A random effects model also allows environmental effects specific to the time of recording to be accounted for and can accommodate genetic differences in the shape of each animal's growth curve. Based on these characteristics the estimates of lamb weights and growth rates from the random effects model were used in this thesis. In the second experiment the impact of production factors on lamb weight at key time points in production were analysed. While several studies have published information on these effects the studies were generally small. Therefore, this analysis acted as a benchmarking for the magnitude of the effects, based on large data. The full expression of the post weaning weight breeding value is depressed with poor nutrition so an analysis was performed to determine the extent to which other forms of nutritional restriction, including lamb and dam factors such as birth type, dam breed and dam age, moderate the expression of the growth breeding value. As expected, factors such as multiple births, which act as a source of nutritional restriction, reduced the full expression of the growth breeding value and hindered lambs reaching expected weights. Muscle oxidative capacity is intrinsically linked to lamb growth and meat quality so in the third experiment the influence of genetic selection for growth on muscle oxidative capacity was examined. Oxidative capacity was indicated by the activity of the oxidative enzyme isocitrate dehydrogenase as well as the concentration of myoglobin in the muscle. As expected, genetic selection for growth reduced isocitrate dehydrogenase activity and myoglobin concentration. The reduction in oxidative capacity with increased growth was due to lambs tending toward a larger matures size and therefore being physiologically less mature at a given weight. The impact of lamb growth on oxidative capacity and meat quality has previously been estimated by the impact of the sire breeding value for growth on these traits or by using hot carcass weight as a proxy for whole of life growth. However the accuracy of these measures of growth is untested. The lamb weights and growth rates derived in the second experiment were used to determine the real impact of growth on oxidative capacity and meat quality. The impact of genetic selection on growth, or the use of hot carcass weight as a proxy for the impact of growth on meat traits, were both shown to be inadequate in quantifying the magnitude of the effect of growth on meat quality traits and indicating how the effect of growth varied with time. In the fourth experiment the impact of lamb growth on intramuscular fat, shear force and consumer overall liking was examined. Intramuscular fat was increased and shear force was reduced with lamb growth. Intramuscular fat and consumer overall liking have a positive association however contrary to expectations growth had no impact on overall liking. This is likely to be due to influences on overall liking other than intramuscular fat. In the final experiment the impact of lamb growth in isocitrate dehydrogenase activity, myoglobin concentration, iron and zinc concentration and meat browning were examined. As hypothesised, myoglobin, iron and zinc concentrations increased with lamb growth. Contrary to expectations isocitrate dehydrogenase activity and meat browning were reduced with lamb growth. Meat browning was thought to reduce due to its strong association with oxidative capacity and thus the oxidative indicator enzyme inverse isocitrate dehydrogenase. These experiments have contributed to the sheep industry at a highly practical and adoptable level showing why the full potential of genetic selection for growth may not be realised and demonstrating the impact of growth on meat eating quality. Currently, increased growth in lambs, particularly in the early stages between birth and weaning has positive effects on meat quality however lambs had few weights recorded between these times so work needs to be done to characterise these associations.

Lo scopo principale di questa tesi è stato quello di indagare se gli effetti di: (i) razza (Bergamasca, Merinizzata Italiana e Sopravvissana); (ii) età di macellazione (40 vs 60 giorni) e (iii) stagione di allevamento (inverno vs autunno) abbiano influenzato le performance di allevamento, macellazione, qualità della carne e composizione di Acidi Grassi (FA) degli agnelli leggeri a marchio “Agnello del Centro Italia” IGP, allevati con sistema transumante nella regione Marche (Italia centrale). Gli agnelli delle razze oggetto di studio hanno mostrato performance di crescita, resa in carcassa e qualità della carne (es. caratteristiche fisiche e chimiche) simili, nonostante si siano evidenziate differenze in alcuni parametri (peso spalle, % proteina, cooking loss, TBARS e ORAC). L'effetto razza ha influenzato significativamente il profilo acidico della carne e del tessuto adiposo ed alcuni parametri legati al valore nutrizionale della carne (PUFA/SFA e indice trombogenico). Lo studio condotto per valutare l’effetto età di macellazione nella razza Bergamasca ha influenzato le caratteristiche quanti -qualitative della carcassa e della carne (drip loss, colore) e anche la composizione acidica del grasso. Considerando sempre la razza Bergamasca, l’effetto stagione di macellazione ha influenzato le caratteristiche della carcassa (corata) e della carne (pH e drip loss a 6 d), come anche il profilo FA della carne e del tessuto adiposo. Questo studio fornisce pertanto ulteriori informazioni sulla qualità di carcassa e carni di agnelli leggeri IGP “Agnello del centro Italia” ottenuti da razze differenti, allevati in stagioni diverse e macellati a differenti età e prodotti con sistema transumante nella regione Marche.
The main aim of the thesis was to investigate the effects of (i) breed (Bergamasca, Italian Merino and Sopravissana), (ii) slaughter age (40 vs. 60 days) and (iii) rearing season (winter vs. autumn) on growth, slaughter traits and meat quality, including fatty acid (FA) composition of “Agnello del Centro Italia” PGI light lambs produced under traditional transhumant sheep system adopted in Marche region (Central Italy). The lambs of the studied breeds showed similar growth performances, carcass traits and meat quality (i.e., physical and chemical characteristics), despite some differences in the investigated parameters that occurred (e.g. % crude protein, cooking loss, TBARS and ORAC). Breed significantly affected FA profile of meat and adipose tissue with Bergamasca showing less favourable meat FA profile (the lowest values of conjugated linoleic acid and the highest thrombogenic index). Higher slaughter age in Bergamasca lambs improved some carcass traits and physical characteristics of meat, it did not influence meat chemical composition or strongly affect meat FA profile, but it worsened chemical composition of adipose tissue. These results suggest 60 days as the optimal slaughter age for Bergamasca to produce slightly heavier carcasses without compromising the quality of lamb meat. Different rearing seasons influenced carcass traits (pluck) and meat quality (pH and drip loss after 6 days of meat storage). FA profile of both meat and adipose tissue was influenced by the rearing season with lambs reared in autumn having adipose tissue with better FA profile for human health. The research provides additional information filling the present gaps of knowledge regarding the quality of “Agnello del Centro Italia” light lambs produced under traditional systems in Marche region for local breeders and consumers.

American lambs are often over-finished and lack consistent quality. It has been suggested that the use of intact ram lambs can decrease USDA YG and improve growth efficiency. However, ram lamb carcasses are underutilized because of potential issues, the most crucial being off-flavor development. Our hypothesis for this study is that U.S. producers can take advantage of intact ram lamb growth and performance with no detriment to product quality, as long as lambs are slaughtered before the attainment of puberty. Three breeds (Hampshire, Dorset, and Columbia), three slaughter weights (light, medium, and heavy) and two sexes (rams and wethers) were evaluated. Results indicate that ram lambs can provide a satisfactory eating experience, however, in one of our studies compounding of maturity and slaughtering intact rams increased incidence of off-flavors. It remains undetermined whether the small differences in sensory characteristics would be detectable by everyday consumers.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
Objetivou-se neste trabalho avaliar os efeitos de dietas contendo silagem inoculada com Lactobacillus plantarum e Bacillus subtilis e suplementadas ou não com amilase sobre a digestibilidade aparente, fermentação ruminal e síntese de proteína microbiana em carneiros, assim como o desempenho e qualidade de carne de cordeiros. Para tanto, dois estudos foram conduzidos, no quais os animais receberam um dos quatro tratamentos (dietas): 1) silagem de milho não inoculada sem adição de amilase na mistura total da ração (MTR); 2) silagem de milho não inoculada e amilase adicionada na MRT; 3) silagem de milho inoculada com 1 × 105 UFC de L. plantarum e 1 × 105 UFC de B. subtilis, sem adição de amilase; 4) silagem de milho inoculada com 1 × 105 UFC de L. plantarum e 1 × 105 UFC de B. subtilis e amilase adicionada na MRT. A enzima utilizada foi a amilase numa taxa de aplicação de 2 g de produto / kg de matéria seca (MS) da dieta (602 unidade dextrinizante (UD) / kg de MS da dieta). A suplementação com amilase em dietas contendo silagem não inoculada aumentou (P=0,045) o consumo de matéria seca dos carneiros quando comparados com aqueles alimentados com silagem não inoculada sem suplementação com amilase (1,311 vs. 1,066 g/d), mas não diferiu dos outros tratamentos. A digestibilidade aparente da MS, MO, PB, FDN e EB aumentou (P<0,01) nos carneiros alimentos com silagem inoculada ou suplementados com amilase, sem interações entre os tratamentos. Os animais alimentados com dietas contendo silagem não inoculada e suplementados com amilase apresentaram alta proporção de ácido propiônico e baixa de ácido acético, e consequentemente baixa relação de aceitoc:propiônico. A síntese de proteína microbiana tendeu a ser maior (P=0,097) nos carneiros alimentados com silagem não inoculada e suplementados com amilase e também nos que receberam dieta contendo silagem inoculada sem suplementação com amilase (8,01; 8,05 g/d, respectivamente). Entretanto, nenhum efeito foi verificado na eficiência de síntese de proteína microbiana. No segundo estudo, cordeiros alimentados com silagem inoculada apresentaram maior consumo de FDN (P=0,019) do que aqueles alimentados com silagem não inoculada (266,5 vs. 245,0 g/d). Cordeiros que receberam dieta contendo silagem inoculada apresentam maior ganho de peso diário (P=0,019) quando comparados àqueles alimentados com silagem de milho não inoculada (232,5 vs. 211,5). A inoculação da silagem aumentou (P<0,05) o conteúdo de ácidos graxos saturados (AGS) e diminuiu (P<0,05) o conteúdo de ácidos graxos insaturados (AGI) (47,55 vs. 46,21% e 52,44 vs. 53,79%, respectivamente), e consequentemente, diminuiu a relação UFA:SFA. A suplementação com amilase no momento da alimentação tendeu (P<0,10) a diminuir a relação AGPI:AGS (0,14 vs. 0,16). O uso de amilases em dietas contendo silagem de milho inoculada não resultou em respostas positivas na digestibilidade e síntese de proteína microbiana de carneiros, bem como não alterou as características de carcaça e qualidade de carne de cordeiros. O uso de dietas contendo silagem de milho inoculada com L. plantarum e B. subtilis e não suplementadas com amilase, aumentou o ganho de peso de cordeiros.
This trial aimed to evaluate the effects of diets containing corn silage inoculated with Lactobacillus plantarum and Bacillus subtilis and supplemented or not with amylase on the apparent digestibility, ruminal fermentation and microbial protein synthesis of wethers as well as, the growth performance and meat quality of lambs. For that, two studies were carried out and in both studies the animals received one of four treatments (diets): 1) Corn silage uninoculated and without amylase added to TMR; 2) Corn silage uninoculated and amylase added to TMR; 3) Corn silage inoculated with 1×105 CFU LP [MA 18/5U] and 1×105 CFU BS [AT553098] without amylase added to TMR; 4) Corn silage inoculated with 1×105 CFU LP [MA 18/5U] and 1×105 CFU BS [AT553098] and amylase added to TMR. The enzyme utilized was amylase at the rate of 2 g of the product / kg of dietary dry matter (DM) (602 dextrinizing unit (DU)/kg of dietary DM). Amylase supplementation on the diet containing uninoculated silage increased (P=0.045) dry matter (DM) intake of wethers compared with wethers fed uninoculated silage without amylase supplementation (1,311 vs. 1,066 g/d), but not differed from others treatments. The apparent digestibility of DM, OM, CP, NDF and GE increased (P<0.01) in wethers fed with inoculated silages or supplemented with amylase, without interaction among inoculants and amylase. Wethers fed diets containing uninoculated silage and supplemented with amylase showed higher propionic acid and lower acetic acid proportion, with low acetic:propionic acid ratio, consequently. Microbial N supply tended to be higher (P=0.097) in wethers fed uninoculated silage with amylase supplementation and inoculated silage without amylase (8.01; 8.05 g/d). However, no effect was verified on the efficiency of microbial N synthesis. In the second study, lambs fed inoculated silage had higher NDF intake (P=0.019) than lambs fed uninoculated silage (266.5 vs 245 g/d). Lambs fed inoculated silage had higher average daily gain (P=0.019) when compared with lambs fed uninoculated silages (232.5 vs. 211.5). The inoculation of silage increased (P<0.05) the content of saturated fatty acid (SFA) and decreased (P<0.05) the unsaturated fatty acid (UFA) (47.55 vs. 46.21% and 52.44 vs. 53.79%, respectively) and consequently decreased the UFA:SFA ratio. The amylase supplementation at moment of feeding trended (P<0.10) to decrease the values of PUFA:SFA ratio (0.14 vs. 0.16). The association of amylase in diets containing inoculated silage did not provided positive responses on the digestibility and microbial N supply of wethers and did not alter the carcass and meat quality of lambs. Inoculation of silage with L. plantarum and B. subtilis improved the average daily gain of lambs when was not associated with amylase supplementation.
CNPq: 141008/2014-8

Orientador: Ricardo Andrade Reis
Coorientador: Juliana Duarte Messana
Banca: Marcia Helena Machado da Rocha Fernandes
Banca: Giovani Fiorentini
Banca: Thiago Fernandes Bernardes
Banca: Odilon Gomes Pereira
Resumo: Objetivou-se neste trabalho avaliar os efeitos de dietas contendo silagem inoculada com Lactobacillus plantarum e Bacillus subtilis e suplementadas ou não com amilase sobre a digestibilidade aparente, fermentação ruminal e síntese de proteína microbiana em carneiros, assim como o desempenho e qualidade de carne de cordeiros. Para tanto, dois estudos foram conduzidos, no quais os animais receberam um dos quatro tratamentos (dietas): 1) silagem de milho não inoculada sem adição de amilase na mistura total da ração (MTR); 2) silagem de milho não inoculada e amilase adicionada na MRT; 3) silagem de milho inoculada com 1 × 105 UFC de L. plantarum e 1 × 105 UFC de B. subtilis, sem adição de amilase; 4) silagem de milho inoculada com 1 × 105 UFC de L. plantarum e 1 × 105 UFC de B. subtilis e amilase adicionada na MRT. A enzima utilizada foi a amilase numa taxa de aplicação de 2 g de produto / kg de matéria seca (MS) da dieta (602 unidade dextrinizante (UD) / kg de MS da dieta). A suplementação com amilase em dietas contendo silagem não inoculada aumentou (P=0,045) o consumo de matéria seca dos carneiros quando comparados com aqueles alimentados com silagem não inoculada sem suplementação com amilase (1,311 vs. 1,066 g/d), mas não diferiu dos outros tratamentos. A digestibilidade aparente da MS, MO, PB, FDN e EB aumentou (P<0,01) nos carneiros alimentos com silagem inoculada ou suplementados com amilase, sem interações entre os tratamentos. Os animais alimentados com dietas contendo ... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: Objetivou-se neste trabalho avaliar os efeitos de dietas contendo silagem inoculada com Lactobacillus plantarum e Bacillus subtilis e suplementadas ou não com amilase sobre a digestibilidade aparente, fermentação ruminal e síntese de proteína microbiana em carneiros, assim como o desempenho e qualidade de carne de cordeiros. Para tanto, dois estudos foram conduzidos, no quais os animais receberam um dos quatro tratamentos (dietas): 1) silagem de milho não inoculada sem adição de amilase na mistura total da ração (MTR); 2) silagem de milho não inoculada e amilase adicionada na MRT; 3) silagem de milho inoculada com 1 × 105 UFC de L. plantarum e 1 × 105 UFC de B. subtilis, sem adição de amilase; 4) silagem de milho inoculada com 1 × 105 UFC de L. plantarum e 1 × 105 UFC de B. subtilis e amilase adicionada na MRT. A enzima utilizada foi a amilase numa taxa de aplicação de 2 g de produto / kg de matéria seca (MS) da dieta (602 unidade dextrinizante (UD) / kg de MS da dieta). A suplementação com amilase em dietas contendo silagem não inoculada aumentou (P=0,045) o consumo de matéria seca dos carneiros quando comparados com aqueles alimentados com silagem não inoculada sem suplementação com amilase (1,311 vs. 1,066 g/d), mas não diferiu dos outros tratamentos. A digestibilidade aparente da MS, MO, PB, FDN e EB aumentou (P<0,01) nos carneiros alimentos com silagem inoculada ou suplementados com amilase, sem interações entre os tratamentos. Os animais alimentados com dietas contendo silagem não inoculada e suplementados com amilase apresentaram alta proporção de ácido propiônico e baixa de ácido acético, e consequentemente baixa relação de aceitoc:propiônico. A síntese de proteína microbiana tendeu a ser maior (P=0,097) nos carneiros alimentados com silagem não inoculada e suplementados com a... (Complete abstract click electronic access below)
Doutor

A carne de borrego é caracterizada por altos teores em ácidos gordos (AG) saturados e baixos níveis de ácidos gordos polinsaturados (AGPI), propriedades que são consideradas prejudicais para a saúde humana. Para atender às recomendações nutricionais é necessário melhorar a sua composição em AG. A principal motivação desta tese foi explorar algumas estratégias nutricionais que permitam melhorar o valor nutricional da fracção lipídica da carne de borrego. Os resultados obtidos mostram que a suplementação das dietas com óleos vegetais ricos em AGPI é uma abordagem eficaz para reduzir a saturação da carne de borrego e aumentar o seu conteúdo em AGPI. Além disso, a suplementação com mistura de óleos de girassol e de linho permitiu aumentar simultaneamente o conteúdo em isómeros conjugados do ácido linoleico e em AGPI n-3 de cadeia longa. A inclusão de bentonite sódica e de Cistus ladanifer em dietas suplementadas com óleo também mostrou ser uma boa abordagem para melhorar a composição em AG da carne de borrego; ABSTRACT: Dietary manipulation to improve the nutritional value of lipids from lamb meat Lamb meat is characterized by high contents of saturated fatty acids and low levels of polyunsaturated fatty acids (PUFA), properties that are regarded as being negative to human health. To meet the nutritional recommendations is necessary improving the fatty acid (FA) composition of lamb meat. The main motivation of this thesis was explored some nutritional strategies that allows improve the nutritional value of lipid fraction from lamb meat. Data presented here show that supplementation of diets with vegetable oils rich in PUFA is an effective approach to decrease the saturation of lamb meat and increase its content in PUFA. Moreover, supplementation with blend of sunflower and linseed oils allowed increase simultaneously meat content in conjugated isomers of linoleic acid and n-3 long chain PUFA. Inclusion of sodium bentonite and Cistus ladanifer in oil supplemented diets also showed to be a good approach to improve the FA composition of lamb meat.

The general objective of this doctoral research was to determine the effects of alternative feeding resources, which are of Mediterranean origin used in lamb and pig production, on meat quality. In the first and second experiments, the lambs were grouped into three to receive different dietary treatments: a barley-based concentrate diet, or two different levels of dried citrus pulp (24% or 35%) to replace barley in concentrate. The meat were stored aerobically for six days at refrigerated temperature, afterwards the colour stability and lipid oxidation (first experiment), and microbial spoilage (second experiment) were evaluated in the muscle longissimus dorsi. Dried citrus pulp strongly reduced meat lipid oxidation, while did not exert effects on colour stability and on microbial growth in meat over storage duration. In the third experiment, the pigs were grouped under dietary treatments concentrate-based finishing diet or two levels of carob pulp (8% and 15%) used to replace concentrate. The lipid oxidative stability and lipid composition were studied in the longissimus thoracis et lumborum. The use of carob pulp as concentrate replacer did not improve the lipid oxidative stability of pork but increased the levels of polyunsaturated fatty acids in meat as compared to concentrate fed pig meat. The findings demonstrate that the dietary citrus pulp or carob pulp could be potentially used as alternative feeds to obtain quality meat. Specifically, the presence of citrus pulp in lamb diets resulted in meat of higher resistance to lipid oxidation, while the inclusion of carob pulp improved the healthy fatty acid contents in pork that is increased in polyunsaturated fatty acids and decreased saturated fatty acids.

The worldwide market for organic foods is growing fast, but New Zealand meat producers have been slow to respond. Specifically, New Zealand producers have little or no organic lamb products for export or domestic sale. Part of the reason for this hesitancy to meet demand with supply is that the nature of the demand and consumer willingness to pay for the product is not well understood. The purpose of this study is to investigate New Zealand organic food consumers’ attitudes towards organic food and production methods and to evaluate consumer willingness to pay for an organic lamb product. Data for this study was collected using computer aided personal interviewing (CAPI) in supermarkets and speciality stores in Christchurch and Wellington. The study questioned consumers about their consumption habits, attitudes towards organic food and production methods and presented choice modelling scenarios to test willingness to pay for different attributes of lamb. Factor analysis is used to group the 12 attitudinal questions into three factors which were then placed into a two step cluster analysis to create consumer segments. Choice modelling was then used to measure consumer preferences for the tested attributes of lamb. From the factor and cluster analysis three distinct consumer segments were found and labelled as Committed Organic Seekers, Convenience Organic Consumers and Incidental Organic Consumers. These labels reflect each group’s organic consumption habits and attitudes towards organic food. The choice modelling results show that there is a willingness to pay for organic lamb. The three identified consumer groups state they would pay a premium of 61%, 44% and 26% respectively for organic lamb over standard pasture raised lamb. This paper gives an insight into consumer attitudes and preferences towards a product that could provide a way for New Zealand farmers to increase their returns. It contributes to the body of knowledge about the likely consumer profiles of regular consumers of organic food. There are only a few other studies that have attempted to measure consumer attitudes and willingness to pay for organic meat, however, the author is not aware of any published example of a study that has specifically investigated demand for organic lamb anywhere in the world. The study provides information about stated willingness to pay for five different attributes of lamb; this information should be of value in assisting the industry by showing which product offerings are likely to generate the highest sale price.

Purpose – the purpose of this research is to explore respondents’ knowledge of regional foods including the pre-product stage i.e. in the landscape. Herdwick lamb and Cumbrian salt marsh lamb are both highly visible in the landscape and form part of the ‘lifescape’ of local residents. Design/method/approach – taking a phenomenological stance the research examines the experiential claims of respondents; means-end chain analysis was selected to gather customer values relating to this broader product concept. Ladder maps were drawn up for each of two sets of twenty respondents residing in the production region of either lamb. Hierarchical value maps are produced to reveal salient connections. Findings – show that respondents hold a very wide range of perceptions, experiences and associations with the ‘pre-products’, which influences their judgement about the freshness, flavour, quality of the meat. The ability to fulfil other functions by buying regional meat became apparent, in particular the need to make a contribution to the local economy, to support the ecology, and to know the place through community interaction. Respondents were found to interact with the landscape on two levels, perception and inner reflection. Practical implications – effective regional food brands may be characterised by branding actions which do not have the food product details at their core. The development of relationships, events and brand communities in a shared place may sustain producers who have their volume output limited by what the land will bear. Originality and value – the limitations of some marketing structures are considered for adaptation including: Boatwright et al.’s (2009) value opportunity analysis and Keller’s (2008) consumer based brand equity model. An opportunity for creation of a new category of attribute, relating to experience of ‘pre-products’ in the landscape is discussed.

Tenderness, juiciness, colour and flavour are the most important meat quality attributes affecting the consumer acceptance. Maintaining the consistency of meat products by avoiding variable quality has become a major concern and great challenge to the meat industry. This in turn will also benefit meat end-users in the marketplace by having more tender meat. The present study was designed to evaluate the overall effects of pre-rigor infusion with kiwifruit juice, which contains the plant protease, actinidin, on lamb quality. A total of 18 lambs (12 months old) were divided into three treatment groups (6 lambs per each treatment). After exsanguination, lamb carcasses were infused (10% body weight) with fresh kiwifruit juice (Ac), water (W) and compared with a noninfusion treatment which acted as a control (C). Samples from different muscle/cuts (longissimus dorsi (LD) vs leg chops) at different post-mortem times (1 day post-mortem vs. 3 wks vacuum packaged storage at 2°C) and display time (0 to 6 days after the post-mortem storage) were analysed to monitor the changes on meat physical properties (e.g., tenderness, temperature, drip and cooking loss, colour), biochemical changes (pH, proteins and lipids) and volatile flavour compounds after the infusion treatments. The most tender meat (lowest shear force values) (P < 0.001) detected in the Ac carcasses post-mortem compared with C and W carcasses demonstrated that kiwifruit juice was a very powerful meat tenderizer, and could contribute to the meat tenderization process efficiently and effectively. Compared with C and W carcasses, the enhanced proteolytic activity (P = 0.002) resulting from the actinidin in kiwifruit juice in Ac carcasses caused degradation of the myofibrillar proteins and the appearance of new peptides during postmortem ageing. A slight positive effect in a*-value (redness) and decreased lipid oxidation, found in leg chops, was thought to be caused by the natural antioxidants in kiwifruit juice. Kiwifruit juice infused into the meat did not alter (P > 0.05) the volatile flavour compound profile indicating that the meat from Ac treated carcasses maintained its natural lamb flavour. No treatment differences were found for the temperature decline (P > 0.05) between the infused treatments and C. The higher rate of pH decline (P < 0.05) found in W carcasses might have contributed to the higher drip and cooking loss. The unbound water in meat might contribute to the higher L*-values (lightness) found in W carcasses. In summary, the proteolytic tenderizing infusion treatment using kiwifruit juice is a feasible approach for the commercial meat industry to increase profits, and also could satisfy the eating quality standards required by the consumers. In addition, tenderizing meat by using kiwifruit juice could also provide the kiwifruit processors an additional option for use of their product to gain a more profitable return.

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Objetivando-se o estudo morfológico dos músculos, qualitativo das carnes e a correlação dos parâmetros avaliados do Gluteus medius, Longissimus e Triceps brachii de animais terminados em diferentes índices de área foliar (IAF) (0,8; 1,4; 2,0 e 2,6%) de pastagem composta por TIFTON 85 (Cynodon spp.) sendo suplementados ou não com concentrado proteico energético (0,7% do peso vivo), utilizou-se 48 cordeiros SPRD, não castrados, com peso médio de 15 kg. Os animais foram confinados pelo período da noite em baias individuais, onde receberam o suplemento com 18% PB. Atingidos o peso corporal médio de 32 kg, os animais foram abatidos e amostras dos músculos Gluteus medius, Longissimus e Triceps brachii foram coletadas para avaliação dos parâmetros morfológicos: frequência, área e área total relativa (ATR). Atingido o post mortem (24 horas após o abate) coletaram-se amostras das porções do Gluteus medius, Longissimus e Triceps brachii para avaliação das características qualitativas: pH, cor, perda de peso por cocção (PPC) e maciez (FC). Não ocorreram interações (P>0,05) entre os IAF e os níveis de suplementação para os valores de pH dos músculos avaliados. No estudo do Gluteus medius, manter os animais em IAF mais elevado e sem suplementação pode ser uma boa alternativa para o alcance de parâmetros desejáveis pelos consumidores de carne ovina. Na avaliação do músculo Triceps brachii, animais mantidos em IAF 1,4 e sem suplementação apresentam maior luminosidade da carne L* e menor teor de amarelo b*. Houve correlação negativa e significativa (P<0,05) entre as fibras FOG e SO e FOG e FG caracterizando o processo de modulação da fibra FOG e refletindo na proporcionalidade da frequência das fibras musculares SO e FG dos músculos Gluteus medius e Longissimus...
Aiming at the morphological study of qualitative muscles of the meat and the correlation of the evaluated parameters Gluteus medius, Longissimus and Triceps brachii animals finished in different leaf area index (LAI) ( 0,8;1,4; 2,0 and 2,6%) of pasture comprising TIFTON 85 (Cynodon spp.) being supplemented or not with energy protein concentrate (0,7% of body weight), we used 48 lambs SPRD, uncastrated, with an average weight of 33,7 lbs . The animals were confined for the duration of the night in individual stalls, where they supplement with 18% crude protein. Reached 32 kg body weight, the animals were slaughtered and samples of the Gluteus medius, Longissimus and Triceps brachii were collected for evaluation of morphological parameters: frequency, area, and total area relative. Hit the post mortem (24 hours after slaughter) and rigor mortis, samples were collected from portions of the Gluteus medius, Longissimus and Triceps brachii and to evaluate the quality characteristics: pH, color, weight loss by cooking and smoothness (shear force). There were no interactions (P>0,05) between the LAI and the levels of supplementation for the pH values of the muscles. In the study of the Gluteus medius, keep animals in higher LAI and without supplementation may be a good alternative to the achievement of desirable parameters by consumers of sheep meat. In assessing Triceps brachii muscle, animals kept in IAF 1,4 and without supplementation have higher meat lightness L* and lower yellowness b*. There was a significant negative correlation (P<0,05) between the SO and FOG, FOG and FG fibers and characterizing the process of modulation, and FOG fiber reflecting the proportionality of frequency of SO and FG muscle fibers of the muscles Longissimus and Gluteus medius...

Thesis (MScAgric (Animal Sciences))--University of Stellenbosch, 2010.
ENGLISH ABSTRACT: The aim of this study was to investigate the effect of feedlot production on the growth and carcass characteristics, as well as the distribution of the main tissues (muscle, fat and bone) and meat quality of Merino, South African Mutton Merino (SAMM) and Dorper lambs. The Merino and SAMM 2008 outperformed (P<0.05) the 2007 SAMM and both Dorper production groups in terms of average daily gain, while the Merino and both SAMM production groups achieved the best feed conversion ratio (P<0.05). The highest percentage A2 graded carcasses was achieved after 42 days under feedlot conditions by the Merino and both Dorper production groups, but it took only 21 days in the feedlot for the SAMM lambs to achieve the same result. Slaughter weight, carcass weight and dressing percentage all increased significantly with an increase in the number of days under feedlot conditions for all three breeds, while a decrease in the percentage head, trotters and red offal was also documented. The fatter retail cuts (thick rib, flank, prime rib and loin) increased (P<0.05) in percentage with an increase in the number of days under feedlot conditions. A significant decrease in the percentage leaner retail cuts (raised shoulder and hind-quarters) was found when the amount of days under feedlot conditions increased. The highest profit is obtained by the prime rib, loin and hind-quarters in a lamb carcass. For the Merino and Dorper lambs these three cuts, or a combination of the three showed the highest combined percentages after 42 and 63 days under feedlot conditions, respectively. The late maturing SAMM lambs achieved the highest percentages for these three cuts after 63 and 84 days under feedlot conditions in 2007 and 2008 respectively. Visceral and renal fat deposition increased throughout the production period for all breeds. The Dorper lambs attained the highest subcutaneous fat depth, and also produced the heaviest, but fattest carcasses. For A2-graded carcasses, Dorper lambs had the highest dressing percentage and lowest subcutaneous fat depth, followed by the SAMM and then Merino breed. A decrease in the percentage muscle and bone was found with an increase in the number of days under feedlot conditions, whilst an increase in the percentage fat was found under the same conditions. Meat quality was mostly affected by the 48h post mortem pH. This pH value is affected by the cooling rate of the carcasses, which in turn is affected by the level of carcass fatness. Carcass fatness increased with an increase in the number of days under feedlot conditions, resulting in a low 48h post mortem pH. A low 48h post mortem pH is accompanied by higher percentages of cooking and drip loss, as well as a high a*-colour reading for all three breeds.
AFRIKAANSE OPSOMMING: Die doel van hierdie studie was om die effek van voerkraalproduksie op die groeivermoë, karkaseienskappe, verspreiding van spier, been en vet, en vleiskwaliteit van Merino, Suid-Afrikaanse Vleismerino (SAVM) en Dorperlammers te bepaal. Die Merino en SAVM 2008 produksiegroepe het hoër (P<0.05) gemiddelde daaglikse toenames getoon as die SAVM 2007 en beide Dorper groepe, terwyl die Merino en beide SAVM produksiegroepe die beste voeromset verhoudings bereik het (P<0.05). Die hoogste persentasie A2 gegradeerde karkasse is na 42 dae in die voerkraal deur die Merino en beide Dorper produksiegroepe geproduseer, terwyl dit slegs 21 dae onder dieselfde toestande vir die SAVM groepe geneem het om dieselfde resultaat te lewer. Daar is ‘n betekenisvolle verhoging in slagmassa, karkasmassa en uitslagpersentasie vir al drie die rasse gevind met ‘n toename in die aantal dae in die voerkraal, terwyl ‘n afname in die persentasie kop, pote en haarslag gevind was. Die persentasie vetter groothandelsnitte (dikrib, dunrib, ribtjop en lendesnit) het toegeneem (P<0.05) met ‘n toename in die aantal dae in die voerkraal. ‘n Betekenisvolle afname in die persentasie van die maerder groothandelsnitte (blad en boude) is gevind met ‘n toename in die aantal produksie dae in die voerkraal. Die hoogste inkomste van ‘n lamkarkas is afkomstige van die ribtjop, lende snit en boude. ‘n Kombinasie van hierdie drie snitte was die hoogste vir die lammers van die Merino en beide Dorper groepe na 42 en 63 dae in die voerkraal onderskeidelik. Die laat volwasse SAVM lammers het die hoogste persentasie van hierdie drie snitte bereik na 63 en 84 dae in die voerkraal vir die SAVM 2007 en SAVM 2008 onderskeidelik. Die neerlegging van pensvet en niervet het voortdurend toegeneem deur die produksieperiode vir al drie rasse. Die Dorperlammers het die hoogste onderhuidse vetneerlegging getoon, maar het ook die swaarste en vetste karkasse geproduseer. Dorperlammers het die hoogste uitslagpersentasie en laagste onderhuidse vetneerlegging vir A2 gegradeerde karkasse gehad, gevolg deur die SAVM en Merino. ‘n Afname in die persentasie spier en been in karkasse is waargeneem namate die lammers langer in die voerkraal was, terwyl ‘n toename in die persentasie vet onder dieselfde omstandighede waargeneem is. Die 48h post mortem karkas pH affekteer die meeste vleiskwaliteit eienskappe. Hierdie pH waarde word weer deur die tempo van karkasafkoeling beϊnvloed, wat op sy beurt deur die vetheidsgraad van die karkas bepaal word. Die vetheid van karkasse het toegeneem met ‘n toename in die aantal dae in die voerkraal, wat ‘n lae pH waarde 48h post mortem tot gevolg gehad het. ‘n Lae 48h post mortem pH waarde het gelei tot hoër persentasies kook- en dripverliese en hoë a* kleurlesings vir al drie rasse.

Video Image Analysis (VIA) is a digital camera based technology that extracts relevant information from images using purpose tailored image processing software. In the present work, the VSS2000 image analysis system from E+V Technology GmbH has been used in a large lamb abattoir to determine the value of carcasses in an objective, consistent and automated way. In this thesis results are reported of several experiments conducted within the framework of two UK-funded projects. The aims of the research were (i) the calibration and validation of the VIAtechnique for the evaluation of lamb carcasses under UK abattoir conditions, with the view to scientifically examine the accuracy and precision of information from the VIA systems as the basis for a value-based marketing system, (ii) to investigate the use of VIA measurements (weights of primal meat yields and carcass dimensional measurements) in sheep breeding programmes to improve carcass and meat quality and (iii) to evaluate the potential of this technology to reward increased carcass quality associated with the use of breeding strategies based on the inclusion of a quantitative trait locus (QTL) for improved muscularity. Accuracy, precision and consistency of The Meat and Livestock Commission (MLC) carcass classification scheme, currently used in UK abattoirs to evaluate carcass quality, was compared against the VIA system in the prediction of various primal joint weights. The results highlighted the advantage of the VIA system being on average 2% more accurate (measured as coefficient of determination: R2) and 12% more precise (measured as root meat squared error: RMSE) in predicting weight of primal meat yields (leg, chump, loin, breast and shoulder) of the lamb carcasses than the MLC carcass classification scheme. The genetic analysis of VIA-based predicted primal joint weights showed substantial additive genetic variance, suggesting that their use in sheep breeding programmes could improve carcass quality either by an improvement of conformation or by an increased weight of the most valuable primal cuts, without an increase in fatness. Favourable associations between VIA primal weights and performance traits indicate that selection based on VIA traits is possible without a negative effect on average daily gain, live weight and cold carcass weight. Although computer tomography (CT) and dissection found in related studies significant effects of a Texel muscling-QTL (TM-QTL) for increased muscularity in the loin region, in the present study they could not be identified by both, the current industry carcass evaluation system for conformation and fatness and the VIA system. A calibration of the VIA system against CT measurements resulted in improved VIA prediction equations for primal meat yields and also showed a moderate potential to estimate loin muscle traits measured by CT and to detect partially the effect of the TM-QTL on these traits. The results of the research demonstrated that VIA is a consistent method to measure carcass composition and that it improved the prediction (accuracy and precision) of primal meat yields compared to the present MLC scoring system. The estimated genetic parameters for VIA primal meat yields suggested that selection for increased lean meat yield from lamb carcass measured using VIA can contribute to genetic improvement of carcass quality without increasing carcass fatness. The results suggest that VIA technology installed in abattoirs could provide the means for the development of a value-based marketing system by paying for weights of the most valuable primal cuts measured using VIA.

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Foram utilizados 48 cordeiros não-castrados, sem padrão racial definido (SPRD), terminados em pasto de tifton-85 sob diferentes índices de área foliar de resíduo pós-pastejo, suplementados ou não (0,7% do peso vivo) por 5 meses, pesos iniciais entre 12 e 15 kg, idade entre 3 e 4 meses. A suplementação aumentou o peso corporal ao abate, perímetro torácico, largura da garupa e largura do tórax, com valores médios de 26,80kg, 73,65cm, 21,52cm, 20,34cm, respectivamente. O índice de área foliar não alterou as características quantitativas in vivo (peso corporal ao abate, comprimento corporal, altura do anterior, altura do posterior, perímetro torácico, largura da garupa e largura do tórax). Os animais suplementados também apresentaram maiores pesos de carcaça quente (12,14kg), peso de carcaça fria (11,58kg) e peso do corpo vazio (22,66kg) em relação aos animais que não receberam. Os demais parâmetros quantitativos da carcaça não foram influenciados pelos tratamentos. As medidas da carcaça não sofreram efeito dos diferentes índices de área foliar, porém os animais que receberam suplemento apresentaram maiores comprimentos externo e interno da carcaça (51,32cm e 58,44cm), e as variáveis comprimento da perna e profundidade do tórax não sofreram influência dos tratamentos. Em relação ao peso dos cortes, os diferentes índices de área foliar não exerceram influência, no entanto os animais que receberam suplementação apresentaram cortes mais pesados. As medidas do músculo Longissimus não sofreram efeito dos diferentes tratamentos, bem como os parâmetros cor, pH, capacidade de retenção de água, perda de peso por cocção, força de cisalhamento e perfil de ácidos graxos, bem como os teores de proteína bruta, extrato etéreo, cinzas, umidade, colesterol e colágeno...
Were used 48 non-castrated lambs without defined breed (SPRD), finished on pasture Tifton-85 under different rates of leaf area after grazing residue, supplemented or not (0,7% of body weight) during 5 months, initial weights between 12 and 15kg, aged between 3 and 4 months. Supplementation increased body weight at slaughter, heart girth, hip width and chest width, with average values of 26,80kg, 73,65cm, 21,52cm, 20,34cm, respectively. The leaf area index did not alter the in vivo quantitative traits (body weight at slaughter, body length, height of anterior hip height , heart girth, hip width and chest width). Supplemented animals also had higher hot carcass weight (12,14 kg), cold carcass weight (11,58 kg) and empty body weight (22,66kg) compared to animals that did not receive. The other quantitative parameters of the carcass were not affected by treatments. Measures of housing did not affect the different rates of leaf area, however, the animals that received supplementation showed higher external and internal lengths of casing (51,32cm and 58,44cm), and the variables length of leg and depth of the chest did not suffer influence of treatments. Regarding the weight of the cuts, the different rates of leaf area did not influence, however the animals that received supplementation showed heavier cuts. Measures of longissimus not suffer effect of different treatments, as well as the parameters color, pH, water holding capacity, weight loss by cooking, shearing force and fatty acid profile, as well as crude protein extract ethereal, ash, moisture, cholesterol and collagen...

Orientadora: Hirasilva Borba
Banca: Emanuel Almeida de Oliveira
Banca: Marco Antônio Trindade
Resumo: Objetivando-se o estudo morfológico dos músculos, qualitativo das carnes e a correlação dos parâmetros avaliados do Gluteus medius, Longissimus e Triceps brachii de animais terminados em diferentes índices de área foliar (IAF) (0,8; 1,4; 2,0 e 2,6%) de pastagem composta por TIFTON 85 (Cynodon spp.) sendo suplementados ou não com concentrado proteico energético (0,7% do peso vivo), utilizou-se 48 cordeiros SPRD, não castrados, com peso médio de 15 kg. Os animais foram confinados pelo período da noite em baias individuais, onde receberam o suplemento com 18% PB. Atingidos o peso corporal médio de 32 kg, os animais foram abatidos e amostras dos músculos Gluteus medius, Longissimus e Triceps brachii foram coletadas para avaliação dos parâmetros morfológicos: frequência, área e área total relativa (ATR). Atingido o post mortem (24 horas após o abate) coletaram-se amostras das porções do Gluteus medius, Longissimus e Triceps brachii para avaliação das características qualitativas: pH, cor, perda de peso por cocção (PPC) e maciez (FC). Não ocorreram interações (P>0,05) entre os IAF e os níveis de suplementação para os valores de pH dos músculos avaliados. No estudo do Gluteus medius, manter os animais em IAF mais elevado e sem suplementação pode ser uma boa alternativa para o alcance de parâmetros desejáveis pelos consumidores de carne ovina. Na avaliação do músculo Triceps brachii, animais mantidos em IAF 1,4 e sem suplementação apresentam maior luminosidade da carne L* e menor teor de amarelo b*. Houve correlação negativa e significativa (P<0,05) entre as fibras FOG e SO e FOG e FG caracterizando o processo de modulação da fibra FOG e refletindo na proporcionalidade da frequência das fibras musculares SO e FG dos músculos Gluteus medius e Longissimus...
Abstract: Aiming at the morphological study of qualitative muscles of the meat and the correlation of the evaluated parameters Gluteus medius, Longissimus and Triceps brachii animals finished in different leaf area index (LAI) ( 0,8;1,4; 2,0 and 2,6%) of pasture comprising TIFTON 85 (Cynodon spp.) being supplemented or not with energy protein concentrate (0,7% of body weight), we used 48 lambs SPRD, uncastrated, with an average weight of 33,7 lbs . The animals were confined for the duration of the night in individual stalls, where they supplement with 18% crude protein. Reached 32 kg body weight, the animals were slaughtered and samples of the Gluteus medius, Longissimus and Triceps brachii were collected for evaluation of morphological parameters: frequency, area, and total area relative. Hit the post mortem (24 hours after slaughter) and rigor mortis, samples were collected from portions of the Gluteus medius, Longissimus and Triceps brachii and to evaluate the quality characteristics: pH, color, weight loss by cooking and smoothness (shear force). There were no interactions (P>0,05) between the LAI and the levels of supplementation for the pH values of the muscles. In the study of the Gluteus medius, keep animals in higher LAI and without supplementation may be a good alternative to the achievement of desirable parameters by consumers of sheep meat. In assessing Triceps brachii muscle, animals kept in IAF 1,4 and without supplementation have higher meat lightness L* and lower yellowness b*. There was a significant negative correlation (P<0,05) between the SO and FOG, FOG and FG fibers and characterizing the process of modulation, and FOG fiber reflecting the proportionality of frequency of SO and FG muscle fibers of the muscles Longissimus and Gluteus medius...
Mestre

Thesis (MScAgric)--Stellenbosch University, 2012.
ENGLISH ABSTRACT: In many parts of the world, soil is depleted of selenium (Se), leading to selenium-poor plants, animals and, therefore, humans. It was recognised that a study to examine the functionality of new products on the market to address this problem was required. The purpose of this research were threefold: to compare the effects of sodium selenite (NaSe) and organically bound selenium sources on small ruminant performance, to investigate the bioavailability of these Se sources, and analyse their influence on carcass characteristics, meat quality and antioxidant capabilities. Fourty growing Döhne Merino wethers from the Southern Cape region, a selenium-deficient area, were used for the study. The animals were all fed the same basal diet in the adaptation period and were then allocated to one of four treatment groups: Control (CT), inorganic selenium (IS), organically bound Se A (OSA) or B: (OSB). The period of supplementation was 90 days. This first study assessed the effect of the different Se sources on growth and Se bioavailability in the wethers. The wethers and the feed they consumed were regularly weighed to determine their growth and feed conversion rate (FCR) in the trial period. To gauge their Se level, blood samples were collected via jugular venipuncture at monthly intervals. The wool around the jugular was shorn and samples were collected on day 0 and day 90 for comparative Se level analysis. Liver, skeletal muscle and kidney samples were collected at day 90, directly after slaughter, to determine the Se level in these tissues. No effect could be reported in the growth and FCR of the wethers between the supplementation groups. For whole blood Se levels there was an effect in the early part of the study, with a greater increase in Se levels for the organically bound Se groups, but in the end no effect on whole blood levels could be seen between the different Se treatments. Neither could any difference between the inorganic Se and organic bound Se treatments be found in the liver – however, the total Se concentration of the wool, kidney and meat samples was greater in those animals offered organically bound Se when compared with those receiving a comparable dose of inorganic Se. The second study evaluated the antioxidant capabilities of the different Se supplements in the wethers. Blood samples were taken monthly for plasma collection to test for Glutathione peroxidase (GSH-Px) activity and total antioxidative capacity (TAC) with the oxygen radical absorbance capacity (ORAC) assay. Liver, skeletal muscle and kidney samples were collected at day 90, immediately after slaughter and measured for GSH-Px activity. With TAC, there was a significant effect for the treatment period between day 0 and day 90, however the treatments did not show any significant difference. No significant differences could be established between the different Se treatments for the GSH-Px analysis in any of the tissues. For the mean plasma values of the treatments no significant differences can be reported, but a significant difference was observed at day 30 in the contrast between the organically bound Se and the other treatment groups. The third study was to evaluate the quality and lipid oxidation of muscle from those wethers supplemented with different Se sources. Skeletal muscle samples were collected at day 90, directly after slaughter to determine this. No differences in the meat quality of the wethers could be detected between Se sources after the 90-day supplementation period. Lipid oxidation was measured by determining TBA reactive substances (TBARS) and once again no differences could be detected. Based on the results found in this investigation, it may be inferred that organically bound Se (OSA & OSB) supplementation will hold a number of advantages for small ruminants over inorganic Se supplementation. Animals fed the organically bound Se had reached adequate Se levels sooner on the organically bounded treatments than the inorganically bounded treated animals. The greater bioavailability of organically bounded Se over inorganic Se was proven by the increased Se levels in certain tissues and organs. Additionally, only the organically bounded Se could find a pathway to the wool, confirming that it was carried in an organic form (probably selenomethionine) in the body. Organically bound Se will therefore have a positive impact on small ruminant health and production, which will result in an indirect advantage for consumer health.
AFRIKAANSE OPSOMMING: Die grond in groot dele van die wêreld word selenium-arm en dit lei na selenium-arm plante, diere en mense. Dit is waargeneem dat ‘n studie wat kyk na die funksionaliteit van nuwe produkte op die mark om die probleem aan te spreek nodig is. Die doelwit van die studie was om verskillende selenium (Se) bronne te vergelyk en die uitwerking daarvan op klein herkouer prestasie te evalueer. Daar is gekyk na die biobeskikbaarheid, invloed daarvan op die karkas eienskappe en antioksidant vermoëns van die verskillende Se bronne. Veertig groeiende Dohne Merino-hamels van die Suid-Kaap-streek, 'n Se arm gebied is gebruik vir die studie. Die diere is almal dieselfde basale dieet gevoer in die aanpassing periode en dan toegeken aan een van vier behandelings: kontrole (CT), anorganiese Se (IS), organies gebinde Se A (OSA) of B: (OSB). Die tydperk van die aanvulling was 90 dae. In die eerste studie is gekyk na die effek van die verskillende bronne van Se op die groei en die biobeskikbaarheid daarvan aan die hamels. Die hamels en voer verbruik, is gereeld geweeg sodat hul groei en voer omset verhouding (VOV) in die proef tydperk te bepaal. Bloedmonsters is versamel deur middel van die jugulêre venipuncture vir die Se vlak bepaling daarvan. Lewer, skeletspier en nier monsters is versamel op dag 90, direk na die slagting vir die Se vlak bepaling. Die wol rondom die nekslagaar is geskeer en monsters is versamel op dag 0 en 90 vir Se vlak analise. Geen effek kan gerapporteer word vir die groei en VOV van die hamels tydens die aanvullings periode nie. Vir die bloed Se vlakke was daar 'n uitwerking in die vroeë deel van die studie, met 'n vinniger toename in Se vlakke vir die organies gebinde Se groepe, maar aan die einde kon geen effek gesien word tussen die verskillende Se behandelings nie. Geen verskil tussen die NaSe en organiese gebonde Se behandelings kon gevind word in die lewer nie. Die totale Se konsentrasie van die wol-, nier-en vleis

The colour of lamb meat on retail display is critical to consumer appeal. Consumers demand a bright red colour in lamb meat and associate dark, pale or browned meat with a lack of freshness and quality. Retailers are forces to downgrade or discount discoloured meat to prevent consumer rejection. Fresh lamb meat may be discoloured due to poor colour development with blooming, or due to browning that develops with time on retail display. The quantity of lamb meat with poor bloomed colour is unknown because lamb carcasses are not routinely graded for meat colour in Australia. The rapid browning of overwrapped lamb meat limits its retail display to only around 2 days. Retailers frequently discount lamb meat to ensure its rapid sale prior to the onset of browning and to thereby limit the economic losses associated with discounting, downgrading or wasting browned meat. Better understanding is required of the factors influencing bloomed colour of lamb meat and its stability on retail display in order to develop strategies to reduce meat discolouration. This thesis evaluates different phenotypic and genotypic factors influencing lamb meat colour in Australia. Bloomed colour (L*, a*, b*, hue angle and chroma) was measured in the loin muscle of over 8000 mixed breed lambs of known genetics produced at 8 sites across Australia over 5 years as part of the Sheep CRC’s INF experiment. The colour stability of the loin muscle was evaluated in over 4000 of these lambs using spectrophotometric measures of meat redness (R630/R580) taken over a 3 day simulated retail display. The first experiment of this thesis examines the influence of production factors and muscle traits on the bloomed colour of lamb loin. Over 40% of the 8165 loin samples were too dark for consumer acceptance, suggesting that dark meat is a substantial problem in the Australian lamb meat industry. Production factors such as lamb slaughter group, production site and year of production had substantial effects on bloomed colour, though these effects could not be attributed to changes in muscle traits such as myoglobin or pH24. Further investigation is required to better understand how production factors influence bloomed meat colour. Of the muscle traits analysed, changes in pH at 24 hours (pH24) had the greatest effect on meat a*, while myoglobin had the greatest effect on meat L*. Increasing lamb age from 140 to 400 days reduced meat L* due to increased myoglobin concentration. These results suggest that industry focus needs to shift to consideration of myoglobin concentration as well as meat pH in order to improve the bloomed colour of lamb meat, particularly meat lightness. The second experiment examines the influence of selection for IMF and lean meat yield on bloomed colour. Increasing IMF from 2 to 8% and shortloin fat weight from 100-500g were positively associated with meat L*, a*, b*, hue angle and chroma. Shortloin muscle weight was negatively associated with these colour parameters, though could largely be accounted for by correlated changes in IMF. The effect of sire breeding values for lamb weight, shortloin muscle depth and fat depth on loin L*, a*, b*, hue angle and chroma were small and varied between lamb sire type, dam breed and sex. Thus selection for increased lean meat yield in lambs will have neutral or positive effects on meat colour, while selection for increased IMF will increase the L*, a*, chroma and thereby the consumer appeal of bloomed lamb meat. The third experiment examines the influence of muscle weight and oxidative capacity on the colour of lamb loin following 72 hours of simulated retail display. Production factors such as slaughter group and site of production had the greatest magnitude effects on meat R630/R580 (redness) after 3 days of display. Increasing loin ICDH activity, reflecting muscle oxidative capacity, reduced R630/R580 at the end of display. Selection for high sire breeding values for shortloin muscle depth increased R630/R580, likely due to an associated reduction in muscle oxidative capacity. Lamb carcass weight also increased R630/R580. Genotypic factors influencing lamb size and growth rate such as sire type and dam breed further support that increased growth rate improves meat colour. These findings suggest that breeding for increased growth rate and muscle weight could improve the colour stability of overwrapped lamb on retail display. The fourth experiment examines the ability to predict the rate of lamb meat browning on display using measures of bloomed colour and information of animal factors that influence colour stability. Simple and partial correlation coefficients between initial boomed R630/R580 and subsequent R630/R580 measures over display were ≤ 0.4, despite incorporation of carcass traits including pH24, lamb age and IMF. Therefore, bloomed colour at the start of display cannot provide a useful prediction of subsequent meat browning. Correlations between 24, 48 and 72 hr measures of R630/R580 were high (> 0.8), suggesting that colour measured from 24 hours of display can provide an accurate prediction of subsequent meat colour. While predicting the rate of meat browning would allow retailers to maximise the display time of lamb, meat colour measured at 24 hrs of display is unlikely to be practical in a retail setting. The predictive ability of 24 hr colour may therefore be limited to use in the development of a breeding value for retail colour. The final experiment examines the use of dietary vitamin E supplementation to improve the colour stability of long-stored lamb meat, particularly meat with high IMF, pH24 and ICDH activity. The capacity of this antioxidant to improve the colour stability of lamb meat was expected to increase in long-stored meat with high IMF, pH24 and ICDH activity due to the anticipated increased oxidative load in this meat. Vitamin E supplementation at 275 mg/kg of feed for 8 weeks prior to slaughter increased R630/R580 throughout the display of lamb loin following 5, 35 and 70 days of storage. However contrary to expectations, vitamin E supplementation had a similar magnitude impact on meat colour stability regardless of storage time prior to the display. Vitamin E did mitigate the negative effect of high IMF on short-stored meat colour, however high IMF did not impact the colour stability of medium or long-stored meat. These results demonstrate that while vitamin E supplementation will improve the colour stability of lamb meat following short, medium or long storage, its greatest impact is on the display colour of short-stored lamb with high IMF content.

Il trasporto degli animali prima della macellazione, ed altri fattori di stress, possono influenzare le caratteristiche chimico-fisiche delle carni, e di conseguenza i valori di pH, TBARS e l’ossidazione di acidi grassi e pigmenti. Questo processo causa peggioramenti qualitativi sia dal punto di vista nutrizionale che commerciale, soprattutto per quanto concerne l’aroma e il colore delle carni, fattori che influenzano enormemente le scelte di acquisto del consumatore. Per questo motivo viene spesso raccomandata una integrazione di antiossidanti tramite la dieta per mantenere gli animali in buona salute e stabilizzare i prodotti dal punto di vista ossidativo. L’antiossidante più utilizzato nelle produzioni animali è senz’altro la Vitamina E. E’ un composto liposolubile che ha la funzione principale di proteggere le membrane cellulari dai danni dell’ossidazione. La forma biologicamente più attiva e più presente in natura è l’-tocoferolo. È ad oggi universalente riconosciuto che una integrazione delle razioni alimentari con -tocoferil acetato stabilizza e controlla l’ossidazione dei lipidi e il decadimento del colore, nelle carni rosse di specie ovine e bovine. Esiste anche una altra modalità di somministrazione della Vitamina E, ossia attraverso iniezioni intramuscolari di DL--tocoferil acetato. Questa modalità ha dimostrato di produrre effetti simili alla somministrazione attraverso la dieta, con risultati però spesso contraddittori, soprattutto per quanto riguarda le performance in vivo. Ad oggi non esistono studi di letteratura che descrivono l’effetto di iniezioni intramuscolari di Vitamina E, sulle performance produttive e sulla qualità della carne di agnelli di razza Laticauda. Questa è una razza autoctona della regione Campania, spesso allevata in piccoli gruppi e con sistema di allevamento semi-estensivo. Deriva da incroci di ovini locali degli Appennini con pecore nord africane dalla coda grassa, importate in Italia nel XVIII secolo. E’ una razza da carne, che presenta una buona prolificità. Lo scopo del presente lavoro di tesi è stato quello di determinare l’effetto di iniezioni multiple di Vitamina E (DL-α-tocoferil acetato) sulle performance produttive, sulla qualità e sulla stabilità ossidativa della carne di agnello. Per la sperimentazione sono stati utilizzati 24 agnelli maschi, di razza Laticauda, di 15 giorni di età. Sono stati suddivisi in due gruppi, somministrando ad ogni animale, settimanalmente, una soluzione fisiologica (Controllo: n=12) oppure DL-α-tocoferil acetato (Vitamina E: n=12; 1500 UI) fino all’età di 57 giorni. Gli animali sono stati macellati a 64 giorni. Il peso a caldo e a freddo è stato registrato e sono state calcolate le rispettive rese, dopo 24 ore di refrigerazione (2–4 °C). E’ stato misurato il pH, il colore, l’area e la capacità di ritenzione idrica (water holding capacity, WHC) del muscolo longissimus dorsi, e le perdite per gocciolamento delle carcasse. Dalla mezzena sinistra, sono stati rimosi i tagli della spalla, della coscia e del lombo e calcolate le relative incidenze sul peso a freddo. Successivamente, sono stati rimossi i muscoli vastus lateralis (VL) e longissimus dorsi (LD) dalla mezzena destra per le analisi di laboratorio. Sul LD è stata misurato il profilo degli acidi grassi, il contenuto di colesterolo, il contenuto di collagene intramuscolare e legami crociati (Idrossilisilpiridinolina, HLP); su LD e VL è stato quantificato il contenuto di α-tocoferolo (µg/g). Sugli gli stessi muscoli, sono stati determinati i TBARS (specie reattive all’acido tiobarbiturico, µg MDA/g tessuto muscolare) a 24, 48, 96 e 192 ore post mortem in conservazione aerobica a 5°C. L’analisi sensoriale è stata effettuata sul coscio sinistro di ogni animale, utilizzando due panel: uno composto da studenti, l’altro da consumatori abituali di carne di agnello. A ciascun panel è stato chiesto di valutare le caratteristiche intriseche della carne – tenerezza, succosità, sapore e accettabilità generale. I risultati sono stati espressi dai giudici tramite schede di valutazione con scala da 1 (molto sgradevole) a 9 (molto gradevole). La somministrazione di Vitamina E non ha avuto effetti significativamente rilevanti sulle performance in vivo e post mortem, ad eccezione dell’incidenza del coscio che è risultata maggiore (P>0.05) negli agnelli del gruppo di trattamento. Il pH, la WHC, l’area del muscolo longissimus dorsi e il colore non sono risultati significativamente diversi tra i gruppi, ad eccezione dell’indice del rosso (a*) che ha fatto registrare valori più elevati (P<0.05) negli agnelli trattamenti. Il trattamento con vitamina non ha avuto effetti significativamente rilevanti sul contenuto totale degli acidi grassi saturi (SFA), fatta eccezione per una quantità lievemente più elevata di acido laurico (C 12:0) ed inferiore (P < 0.01) di acido eptadecanoico (C 17:0) nel gruppo vitamina. Lo stesso risultato è stato riscontrato per gli acidi grassi monoinstraturi (MUFA), fatta eccezione per il contenuto più basso (P < 0.01) di C 17:1 e più alto di C 18:1 n-9 trans (P < 0.05) e C 22:1 (P < 0.01) nel gruppo della vitamina E. L’acido oleico (C18:1 n-9 cis) è risultato quello con la concentrazione più elevata (40-41%), seguito dal palmitico (20-21%) e dallo stearico (14-15%). Un effetto significativamente positivo (P < 0.01) è stato riscontrato sul contenuto totale di acidi grassi polinstaturi (PUFA), più elevati nel gruppo della vitamina E. Il più abbondante PUFA è risultato essere l’acido linoleico (C 18:2 n-6), con valori simili trai gruppi (7.95 e 8.07%, in C e V rispettivamente). Il secondo più rappresentativo è l’acido linolenico (C 18:3 n-3), che è contenuto principalmente nelle essenze verdi. Significativamente maggiore è risultato essere il contenuto di PUFA a lunga catena n-3 nel gruppo vitamina E: acido eicosapentanoico (EPA, C20:5 n-3, P < 0.05), docosapentaenoico (DPA, C22:5 n-3, P < 0.01) e docosaesaenoico (DHA, C22:6 n-3, P < 0.06). Anche il C 22:2 è risultato significativamente più alto (P < 0.01). Alla luce di ciò, il contenuto totale di n-3 è risultato maggiore (P < 0.01) negli agnelli trattati rispetto al controllo; mentre non sono state riscontrate differenze significativamente rilevanti per quanto concerne il contenuto totale di n-6. Il rapporto n-6/n-3 è risultato inferiore negli agnelli trattati (2.33 versus 3.62 in V e C, rispettivamente; P < 0.01). Il rapporto P/S invece è superiore (P < 0.01) negli agnelli trattati, anche se il valore ottenuto risulta inferiore a quello raccomandato (0.4-0.7). Anche l’indice trombogenico (TI) è stato influenzato dal trattamento, ed è risultato inferiore (P < 0.01) nel gruppo vitamina. Il contenuto di colesterolo non è risultato diverso (P > 0.05) tra i gruppi (78.78 versus 79.01 mg/100g in C e V, rspettivamente), ma leggermente più elevato se paragonato con altri studi su altre razze. La concentrazione di collagene (22.59 e 22.57 μg/mg in C e V, rispettivamente) e di HLP (4.37 e 4.59 μg HLP/mg in C e V, rispettivamente), come anche la stabilità delle fibre di collagene (0.135 e 0.142 mol HLP/mol di collagene in C e V, rispettivamente) non sono state influenzate (P > 0.05). Al contrario il trattamento con la vitamina E ha notevolmente incrementato (P < 0.001) il contenuto di DL-α-tocoferolo in entrambi i muscoli (longissimus dorsi: 0.92 versus 6.41 µg/g in C e V, rispettivamente; vastus lateralis: 0.99 versus 7.31 µg/g in C e V, rispettivamente) e ha incrementato la conservabilità della carne. Questo è risultato evidente dal momento che i livelli di TBARS sono stati significativamente più bassi (P < 0.01) negli agnelli trattati con vitamina E (longissimus dorsi and vastus lateralis muscles) a 24, 48, 96 e 192 h di conservazione aerobica a 5°C. Il panel test ha mostrato che sia gli adulti che gli studenti hanno gradito entrambi i tipi di carne, pur preferendo leggermente di più la carne degli agnelli trattati con vitamina E (piacevolezza generale: 7.24 e 6.97 rispettivamente; P > 0.05). Sia gli studenti che gli adulti hanno espresso un maggior gradimento per la carne del gruppo sperimentale per quanto riguarda i descrittori della tenerezza (6.66 versus 5.70, rispettivamente; P < 0.05) e succulenza (6.39 versus 5.00; P <0.05). Alla luce dei risultati ottenuti, possiamo concludere che l’utilizzo di Vitamina E per via intramuscolare, in agnelli di razza Laticauda, è consigliabile per ottenere carni con un più elevato valore nutrizionale e commerciale.
Transporting animals to the slaughterhouse can increase the susceptibility of meat quality and, therefore, influence the value of pH, TBARS and the oxidation of fatty acids and pigments. Lipid oxidation cause negative changes on structure and nutrition value such as meat flavour, odour and colour: it is well know that colour is the characteristic that more affects the decision of the consumer to purchase. For this reason a supply of antioxidants is recommended to preserve the health of animals and the oxidative stability of their products. One of the most widely used antioxidants in animal diet is vitamin E. It is a lipid soluble and chain breaking antioxidant that protect cellular membranes against oxidative damages. The most active and natural form of vitamin E is -tocopherol. It is now accepted that dietary supplementation with -tocopheryl acetate controls lipid oxidation and colour deterioration in red meat like lambs and beef. In literature has been reported that intramuscular injections of tocopherols had a quite similar effect to the supplementation of vitamin E in diet. However, controversial information regarding the productive performances are also showed in some works on lambs. No information exists in literature on performance and meat quality traits of Laticauda lambs injected with Vitamin E. Laticauda is an autochthonous breed of Campania Region in Italy, that is usually reared by small family farms under semi-extensive systems. It derives from crossbreeding local sheep from the Appennines breed with fat-tailed North African sheep, imported in the XVIII century. Laticauda breed has a prevailing attitude toward meat production, associated to a good prolificacy. In the light of the above mentioned, the aim of the study was to determine the effect of DL-α-tocopheryl acetate injections on carcass and meat quality traits in growing lambs. Twenty-four 15-d-old Laticauda male lambs were randomly allotted to two groups: control (C, n =12) or vitamin E-treated (V, n=12). From the beginning of the study (15 days of age) until day 57 of age, each lamb of the V group received, weekely, i.m. injections of DL-α-tocopheryl acetate (right gluteus) in aqueous solution (Vitalene® E, Fatro, Bologna) for seven weeks for a total dose of 1,500 IU. The first injection consisted of 150 UI (3ml of Vitalene), while the other 6 injections consisted of 225 IU (4.5 ml of Vitalene). C group lambs received injections of physiological saline. The animals were slaughtered at 64d of age. Hot and cold carcass weights were recorded and dressing percentages were calculated after dressing and chilling (2–4 °C for 24 h). After chilling, pH, colour, area, water holding capacity of M. longissimus dorsi (LD) were measured and shrink losses were calculated. After the refrigeration period (24 h at 2-4 °C), from the left side of the carcass the pelvic limb, loin and shoulder were removed and theirs percentage was calculated based on cold carcass weight. Vastus lateralis (VL) and longissimus dorsi (LD) muscles were removed for laboratory analyses (LD: fatty acids, cholesterol, intramuscular collagen, crosslinks; LD and VL: α-tocopherol content). For the same muscles TBARS (µg MDA/g tissue) at 24, 48, 96 and 192 h post mortem were measured during aerobic display at 5°C. Sensory analysis was performed on the pelvic limb from the left side of each lamb carcass, having two panels: one for the students, and the other one for customary consumers of lamb meat. Each panellist was required to evaluate the sample considering the intrinsic characteristics of the meat – tenderness, juiciness, flavour and overall acceptability (general pleasantness) – according to an unstructured line scale ranging from 1 (“very unpleasant”) to 9 (“very pleasant”). Vitamin E administration did not influence significantly live weight, carcass traits, except the incidence of pelvic limb, significantly higher in V group lambs; LD quality traits did not differ between the experimental groups, except for the red colour value (a*) that was higher (P<0.05) in lambs of vitamin E group. Treatment with vitamin E did not significantly affect the total SFA content and the proportion of single SFA, except for a slightly higher (P < 0.08) content of lauric acid (C 12:0) and lower (P < 0.01) content of eptadecanoic acid (C 17:0) in V group. Likewise, vitamin E treatment did not affect the total MUFA amount, except for a lower (P < 0.01) content of C 17:1 and higher C 18:1 n-9 trans (P < 0.05) and C 22:1 (P < 0.01) in V group. The oleic acid (C18:1 n-9 cis) was the most concentrated fatty acids (40-41%), followed by palmitic (20-21%) and stearic acids (14-15%). Vitamin E treatment positively affected the total PUFA content being higher (P < 0.01) in the V group compared with the control group. The vitamin E treated group had a significant higher amount of n-3 long chain PUFA: eicosapentaenoic fatty acid (EPA, C20:5n-3, P < 0.05), docosapentaenoic fatty acid (DPA, C22:5n-3, P < 0.01) and docosahexaenoic fatty acid (DHA, C22:6n-3, P < 0.06). Also vitamin E group had higher (P < 0.01) content of C 22:2. In light of this, the total n-3 FA content was higher (P < 0.01) in treated lambs compared with the control group; while, no significant differences were found for the total n-6 FA amount. The n-6/n-3 ratio was lower in treated lambs (P < 0.01). The P/S ratio was higher (P < 0.01) in treated lambs. Trombogenic index was affected by the treatment being lower (P < 0.01) in vitamin E group. Cholesterol content was found to be not significant (P > 0.05) between groups (78.78 versus 79.01 mg/100g in C and V, respectively). Collagen characteristics were not significantly (P > 0.05) influenced by the treatment. The treatment with vitamin E markedly increase (P < 0.001) the content of DL-α-tocopherol in both muscles (longissimus dorsi: 0.92 versus 6.41 µg/g in C and V, respectively; vastus lateralis: 0.99 versus 7.31 µg/g in C and V, respectively) and increases the meat shelf life. This was evident since muscle tissue lipoperoxidation levels (TBARS) were significantly lower (P<0.01) in vitamin E injected lamb meat (longissimus dorsi and vastus lateralis muscles) at 24, 48, 96 and 192 h post mortem, during all the aerobic display at 5°C. The panel test showed that both the adult and the student judges, enjoyed both types of meat, giving a slightly higher point for the lamb that was injected with vitamin E if compared to the other type of meat (7.24 versus 6.97 respectively; P > 0.05). Therefore, both expressed a greater pleasure with the meat produced from lamb injected with vitamin E if compared to the meat of control group, as regard the descriptor of tenderness (6.66 versus 5.70, respectively; P< 0.05) and juiciness (6.39 versus 5.00; P < 0.05). At the light of the above, the conclusion of this study is that the intramuscular administration of vitamin E can be recommended to obtain meat with a higher nutritional and commercial value.

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Objetivou-se avaliar as características da carcaça e de seus não componentes em cordeiros alimentados com fenode amoreira (FA) no concentrado em substituiçãoao farelo desoja e milho,além das características qualitativas de hambúrguerese linguiças elaboradas com fígadoovino. Foram utilizados 24 cordeiros com 15,48 ±0,07 kg de peso corporal alojados em baias individuais eabatidos aos 32,20 ± 0,49 kg. Os tratamentos foram: 0%FA: cana forrageira + concentrado, 12,5%FA: cana forrageira + concentrado + 12,5% defeno de amoreira na MS e 25%FA: cana forrageira + concentrado + 25%de feno de amoreirana MS. Os hambúrgueres e linguiças foram elaborados com carne de cordeiros provenientes do tratamento controle do experimento acima anterior, sem ou com (15 e 30%) inclusãode fígado ovino em substituição à carne de pescoços e costelas desossadas. Odelineamento experimental foi o inteiramente casualizadosendo os dados submetidos à análise de variância e regressãopelo programa estatístico Sisvar a 5% de significância.A inclusão do fenodeamoreira promoveu efeito linearcrescente para a profundidade do tórax, índice de musculosidade da perna e relaçãomúsculo:osso eefeito linear decrescente, para o índice de compacidade da carcaça,peso da paleta, área de olho de lombo obtida pelo ultrassom, peso e comprimento do fêmur, peso dapele e pesoe porcentagemdas extremidades dos membros. Houve efeito linear crescentepara teoresde sódio no fígado, potássio no coração e sódio, potássio, cálcio, ferro e cobre na língua de cordeiros recebendo feno de amoreira.A inclusão do fígado nos processados comcarne ovina promoveu aumento na luminosidade e efeitoquadrático para a intensidade de vermelho. As variáveis pH, capacidadede retenção de água, força de cisalhamento, oxidação lipídica no dia 0 e 45 dias, teor de gordura e sabor dos hambúrgueres tiveram efeito quadrático...
The aim of this study was to evaluate non-components and carcass traits of lambs fed concentrate containing mulberry hay (FA) as a substitute for soybean and corn. Further, qualitative traits of hamburgers and sausages made with sheep liver were evaluated. Twenty-four lambs with 15.48 ± 0.07 kg live weight were allotted in individual pens and slaughtered at 32.20 ± 0.49 kg. The treatments were: 0%FA: sugarcane forage + concentrate, 12.5%FA: sugarcane forage + concentrate + 12.5% mulberry hay, dry basis and 25%FA: sugarcane forage + concentrate + 25% mulberry hay, dry basis. The hamburgers and sausages were elaborated with lamb meat from the control treatment of the experiment cited above, with the inclusion (15 and 30%) or not of sheep liver as a substitute for neck and ribs. A completely randomized design was used and data were submitted to an analysis of variance and regression analysis using the Sisvar software with a 5% significance level. A linearly increasing for chest depth, leg muscularity and muscle: bone ratio were observed with the inclusion of mulberry hay and a linearly decreasing for carcass compactness index, palette weight, loin-eye area through ultrasound, femur weight and length, skin weight and limb percentages. A linearly increasing effect for sodium levels in the liver, potassium in the heart and sodium, potassium, iron and cupper in the tongue were observed in the lambs fed mulberry hay. An increasing luminosity and a quadratic effect for red intensity were observed with the inclusion of liver in the meat products of sheep meat. The pH, water-holding capacity, shear force, lipid oxidation at 0 and 45 days, fat level and the flavor of hamburgers showed quadratic effects...

Mestrado em Engenharia Alimentar - Instituto Superior de Agronomia
Due to the decrease in consumption of ovine meat registered in the Spanish market, Oviso financed a research study on the optimization of lamb legs commercialization, in order to transform them into a more attractive product. As such, the restructured food technology was tried in order to obtain an added-value lamb meat product obtained from pieces of low commercial value (due to the high concentration of connective tissues, muscular reclamation, et cetera). Nowadays, as a consequence of the increasing demand for minimally processed food, cold union technology an interesting option for making raw restructured meat, ready to be commercialized in fresh conditions. In this study, two cold union agents were used: transglutaminase and alginato. The restructured lamb leg meat loafs were prepared and optimized for future industrial production. Two alginate procedure were used (diluted in water - AlgH2O, and added without any previous dilution - AlgPó) and in another, microbial transglutaminase with sodium caseinate (TG) as a binding agent (salt free), in low temperature systems (4ºC). Physical, chemical and sensory parameters were determined by, instrumental (TPS, Kramer and color) and chemical (fat, pH, humidity and protein) and sensory analysis (tasters panel), respectively. In conclusion the product obtained with alginatos directly added to the meat (AlgPó), showed better physical, chemical and technological proprieties for further industrial production.

Orientadora: Hirasilva Borba
Banca: Emanuel Almeida de Oliveira
Banca: Greicy Mitzi Bezerra Moreno
Resumo: Foram utilizados 48 cordeiros não-castrados, sem padrão racial definido (SPRD), terminados em pasto de tifton-85 sob diferentes índices de área foliar de resíduo pós-pastejo, suplementados ou não (0,7% do peso vivo) por 5 meses, pesos iniciais entre 12 e 15 kg, idade entre 3 e 4 meses. A suplementação aumentou o peso corporal ao abate, perímetro torácico, largura da garupa e largura do tórax, com valores médios de 26,80kg, 73,65cm, 21,52cm, 20,34cm, respectivamente. O índice de área foliar não alterou as características quantitativas in vivo (peso corporal ao abate, comprimento corporal, altura do anterior, altura do posterior, perímetro torácico, largura da garupa e largura do tórax). Os animais suplementados também apresentaram maiores pesos de carcaça quente (12,14kg), peso de carcaça fria (11,58kg) e peso do corpo vazio (22,66kg) em relação aos animais que não receberam. Os demais parâmetros quantitativos da carcaça não foram influenciados pelos tratamentos. As medidas da carcaça não sofreram efeito dos diferentes índices de área foliar, porém os animais que receberam suplemento apresentaram maiores comprimentos externo e interno da carcaça (51,32cm e 58,44cm), e as variáveis comprimento da perna e profundidade do tórax não sofreram influência dos tratamentos. Em relação ao peso dos cortes, os diferentes índices de área foliar não exerceram influência, no entanto os animais que receberam suplementação apresentaram cortes mais pesados. As medidas do músculo Longissimus não sofreram efeito dos diferentes tratamentos, bem como os parâmetros cor, pH, capacidade de retenção de água, perda de peso por cocção, força de cisalhamento e perfil de ácidos graxos, bem como os teores de proteína bruta, extrato etéreo, cinzas, umidade, colesterol e colágeno...
Abstract: Were used 48 non-castrated lambs without defined breed (SPRD), finished on pasture Tifton-85 under different rates of leaf area after grazing residue, supplemented or not (0,7% of body weight) during 5 months, initial weights between 12 and 15kg, aged between 3 and 4 months. Supplementation increased body weight at slaughter, heart girth, hip width and chest width, with average values of 26,80kg, 73,65cm, 21,52cm, 20,34cm, respectively. The leaf area index did not alter the in vivo quantitative traits (body weight at slaughter, body length, height of anterior hip height , heart girth, hip width and chest width). Supplemented animals also had higher hot carcass weight (12,14 kg), cold carcass weight (11,58 kg) and empty body weight (22,66kg) compared to animals that did not receive. The other quantitative parameters of the carcass were not affected by treatments. Measures of housing did not affect the different rates of leaf area, however, the animals that received supplementation showed higher external and internal lengths of casing (51,32cm and 58,44cm), and the variables length of leg and depth of the chest did not suffer influence of treatments. Regarding the weight of the cuts, the different rates of leaf area did not influence, however the animals that received supplementation showed heavier cuts. Measures of longissimus not suffer effect of different treatments, as well as the parameters color, pH, water holding capacity, weight loss by cooking, shearing force and fatty acid profile, as well as crude protein extract ethereal, ash, moisture, cholesterol and collagen...
Mestre

O objetivo do presente trabalho foi analisar o comportamento do consumidor de carne ovina considerando a percepção de qualidade através das pistas e atributos de qualidade. Foram utilizados dois métodos de entrevistas: presencial com consumidores de uma loja especializada em carnes na cidade de Porto Alegre, Estado do Rio Grande do Sul, e questionários online. Ao total, foram entrevistadas 207 pessoas, sendo que 100 responderam o questionário no formato presencial e 107 no formato online. O questionário aplicado nas entrevistas foi classificado como estruturado e possuía cinco partes. A primeira, relacionada ao hábito de consumo de carnes de uma maneira em geral, a segunda parte, ao hábito de consumo da carne ovina, a terceira, relacionada ao hábito de consumo dos compradores de carne ovina, a quarta parte, sobre os estilos de vida dos entrevistados e a quinta e última referente a características sóciodemográficas. A terceira parte era apenas respondida por aqueles consumidores que também eram compradores de carne ovina. A análise estatística foi realizada por meio do software Standards Aligned System SAS/STAT 9.2, a partir do procedimento GLIMMIX (GLMM) (SAS, 2008). Inicialmente foi feita uma distribuição de frequência dos dados obtidos e posteriormente, foi analisada a possibilidade da formação de Clusters. Para a caracterização e melhor descrição de cada cluster utilizou-se a Análise Discriminante (STEPDISC), porém a estatística mostrou que não havia o nível de confiança suficiente para a formação de clusters. Na continuação da análise, foi realizada uma correspondência (The CORRESP procedure) e por último uma regressão estatística entre as variáveis, frequência de consumo e faixa etária, correlacionando a informação com as perguntas relacionadas aos atributos de qualidade. Os resultados obtidos demonstram uma tendência da carne ovina ser consumida pelo sexo masculino. No momento da compra, os homens e aqueles entrevistados que se encontraram na faixa etária de 31 a 40 anos possuíam maior disposição em participar na compra de carnes. As pistas de qualidade mais importantes nos atributos de busca em relação à frequência de consumo foram a cor e a gordura externa, e as que foram consideradas de mais baixa importância foram a marca e a propaganda. Nos atributos de confiança, a origem e a categoria do animal foram as mais importantes em relação à frequência de consumo. A influência da idade na percepção dos atributos de busca segue o mesmo comportamento da frequência de consumo, destacando que a gordura possui uma importância maior nas faixas etárias mais jovens. No caso dos consumidores com mais idade, estes dão maior importância para a embalagem e para as variedades de cortes. No atributo de confiança, as quatro pistas de qualidade possuíram maior importância para os consumidores mais jovens e as pistas de experiência seguem o mesmo comportamento.
The aim of this study was to analyze the consumer behavior of lamb meet considering the perception of quality cues and its quality attributes. Two interview methods were used: face-to-face interviews with consumers of a butcher boutique located in the city of Porto Alegre, state of Rio Grande do Sul, and online questionnaires. In total, 207 people were interviewed in which 100 people answered the face-to-face questionnaire and a 107 the online questionnaire. The questionnaire applied in the interviews is classified as structured and owns five chapters. The first one related to the habits of meat consume in a general way, the second chapter, considers the habits of lamb meat consume, the third chapter, regards the habits of lamb consume buyers, the fourth chapter, investigates about interviewers lifestyle and the fifth and last chapter refers to socio demographic characteristics. The third chapter was only answered by those consumers who actually were also buyers of lamb meet. The statistical analysis was performed using the Standards Aligned System software SAS / STAT 9.2, The GLIMMIX Procedure (GLMM) (SAS, 2008). Initially, a frequency distribution of data obtained was made and subsequently the possibility of forming clusters analyzed. To better characterize and descript clusters the Discriminant Analysis (STEPDISC) was used, however, statistical shows there was no sufficient confidence level for the formation of clusters. In further analysis, we performed a data correspondence (The CORRESP procedure) and finally a statistic regression between variables, frequency of meat consumes and age group, correlating the information with the questioning related to the quality attributes. The results show that there is a trend in lamb consume that are higher between male sex representatives. At the specific moment of purchase, men and those respondents who are within the age group of 31 to 40 years have a higher willingness to participate in the purchase of meat. The quality cues most important in search quality attributes regarding the frequency of consumption were the color and external fat and those considered of lower importance were branding and advertising. In confidence attributes, origin and animal category were the most important in relation to the frequency of consumption. The influence of age in the perception of search attributes follows the same behavior of frequency of use, highlighting that fat having a great importance within the younger age groups. For older consumers, the packaging and to the varieties of cuts have greater importance. When analyzing confidence attributes, the four quality cues are the ones with greater importance to youngest consumers group and the experience cues follows the same behavior.

Fifty-nine mature "Western" (Suffolk x Rambouillet) and 71 mature ¼ - Finn (Suffolk x Finn-Rambouillet) ewes were bred to Suffolk-Hampshire rams to lamb in either spring (March) or fall (September). Effects of ewe breed type and lambing season on ewe fertility (ewes lambing/ewes exposed), prolificacy (lambs born/ewe lambing) and lambing date, and on lamb birth weight, 30-d survival, and average daily gain (ADG) to 55 d and to weaning were evaluated. Fertility was higher in spring than in fall (94 vs 64%, P<.01). Use of %-Finn ewes tended to increase fertility in fall lambing (69 vs 59%, P<.25) but not in spring (94 vs 93%). Use of ¼ -Finn increased prolificacy by .36 lambs; fall lambing reduced prolificacy by .49 lambs. Lambs of Western ewes were born 5 d later (P<.01) and .6 Ib heavier (P<.001) than lambs of ¼ -Finn ewes. Lamb survival and ADG to 55 d and to weaning were not affected by ewe breed. Season affected ADG: fallborn lambs grew faster to 55 d (P< .05) and to weaning (P< .001) than spring-born lambs, attributable to differences in environmental factors. Effect of weaning on growth of spring-born lambs grazing summer pasture was analyzed. Spring lambs weaned at 90 d of age to graze independently grew more slowly and were older at market weight than lambs remaining with their dams on native perennial pastures (.24 vs .42 lb/d, P<.001; 201 vs 186 d of age, P<.001). Use of millet (Pennisetum americanum [L.] Leeke) as annual mid-summer forage and turnip (Brassica rapa L.) as annual late-fall forage were investigated. Dry ewes grazing millet lost weight in one yr, but averaged .23 Ib/d gain in a second yr; weaned lambs grazing pearl millet averaged .32 lb/d gain over 2 yr. Lactating and dry ewes grazing turnip had average weight changes of -.37 and +.11 lb/d, respectively. Budgets for production systems were constructed. Variable revenues and expenses for all combinations of ewe breed type, lambing season, weaning treatment, and annual forage use were integrated into an annual production system. The most profitable production systems were those that exhibited the greatest reproductive efficiency, required the least drylot time to finish lambs, and maximized use of perennial pastures.
Master of Science

Internal parasites (strongylid gastrointestinal helminths) have been reported to decrease lamb productivity in extensive grazing sheep enterprises. Increased interest into intestinal, protozoan parasites; Cryptosporidium and Giardia, has arisen due to their potential public health risks. Little research has examined their prevalence and impact on productivity in extensively managed livestock. Despite molecular diagnostic techniques having the capability to facilitate rapid identification, improve control and enhance prevention strategies for disease pathogens, little investigation has been conducted to compare molecular tests with traditional diagnostic methods. Longitudinal studies observed that 47–81% of lambs sampled, tested positive for Cryptosporidium or Giardia at least once in their lives over five sampling occasions. Cryptosporidium xiaoi and G. duodenalis assemblage E were the most common species/genotypes isolated from Pingelly (Farm A) and Arthur River (Farm B). Zoonotic species/genotypes were also isolated but in low numbers. Cryptosporidium xiaoi was isolated on two occasions from dam water on Arthur River, while C. ubiquitum and G. duodenalis assemblage E were detected in dam water from Frankland. A novel, possibly new genotype (sheep genotype I) was identified in six Cryptosporidium isolates from Arthur River. Cryptosporidium parvum and C. ubiquitum were the most common species detected in Boyup Brook and Kojonup flocks. Statistical analyses revealed lambs positive for Cryptosporidium on at least one sampling occasion had lighter HCWs and lower dressing percentages when compared to lambs never positive for Cryptosporidium for Farms A and B, respectively. On Farm B, lambs positive for Giardia on at least one occasion had lighter HCWs and lower dressing percentages when compared to lambs never positive for Giardia. Cryptosporidium-positive lambs at the second sampling were 3.84–4.72 times more likely to have non-pelleted faeces (faecal consistency score [FCS] ≥ 3), when compared to Cryptosporidium-negative lambs for Farms A and B. Lambs on Boyup Brook and Kojonup farms that were positive for Cryptosporidium, Giardia or both, were 2.4–14.0 times more likely to have non-pelleted faeces. Furthermore, a higher number of internal parasites detected per lamb was associated with lower body condition score (BCS) and higher FCS on the Boyup Brook and Kojonup farms. Cryptosporidium-positive lambs were 3.36–2.96 times more likely to have moderate to severe breech fleece faecal soiling scores (3 – 5), when compared to Cryptosporidium-negative lambs at the second sampling for Farms A and B. Live weight, growth rate and BCS were inconsistently associated with protozoa detection across different samplings and farms. A further study compared the performances of two lamb flocks exposed to different natural strongylid larval challenges. A new innovative, molecular approach was developed to recover strongylid larvae from pasture, which had a strong, negative correlation (r2=0.91–0.95) with pasture larval counts used to detect and quantify strongylid larvae species on pasture. Flock L (exposed to a low larval challenge) had greater dressing percentages greater than Flock S (exposed to a higher larvae challenge). Within flock analyses of the Frankland flocks found lambs positive for Giardia at least once had lighter HCWs and lower dressing percentages, when compared to lambs never positive for Giardia. A written questionnaire which surveyed 139 (41.4%) meat lamb enterprise owners/managers in southern Western Australia, found evidence of diarrhoea was reported on 64.8% of farms. A binary logistic regression analysis revealed that the source of livestock drinking water was associated with the incidence of diarrhoea. Lamb flocks that sourced water from a dam, were 117 times more likely to have active or recent evidence of diarrhoea. Overall, 10.1% and 14.4% of respondents were aware of Cryptosporidium and Giardia, respectively. Comparison between a molecular diagnostic technique (identifying strongylid species by screening genomic DNA extracted directly from faeces) and the traditional McMaster WEC method, found high levels of agreement (kappa statistic ≥0.93) between the test results for detecting patent strongylid infections in two separate epidemiological studies. The findings that some lambs tested negative for strongylid infections while grazing pastures known to be infested with larvae, together with the strong correlations between WEC and the number of strongylid species detected per lamb, both suggest that strongylid eggs are the likely main source of strongylid DNA. The findings of this thesis suggest that molecular identification of internal parasites is potentially negatively associated with phenotypic performance traits of lambs. Protozoa-positive lambs had reduced production performances (lighter carcase weights and reduced dressing percentage), when compared to protozoa-negative lambs. For such molecular techniques as that were employed in this research to be introduced into routine veterinary diagnostics, they need to: (1) quantify the magnitude of infections, (2) provide cost-benefits to sheep producers, (3) display consistent associations/correlations with phenotypic performance traits of livestock and (4) be cost-beneficial for diagnostic laboratories to conduct (sales volume and equipment costs). The future development of multiplex, real-time, quantitative PCR (qPCR) assays capable of detecting and quantifying multiple pathogen infections (parasites and bacteria) in a single assay, would facilitate the uptake of such tests for both veterinary and human diagnostics

Understanding the impact of acute and chronic stress incurred during the pre-slaughter period is important to maximise lamb meat quality and yield as well as maintaining high levels of animal welfare. This thesis quantified the level of acute and chronic stress at slaughter utilising plasma indicators reflecting acute stress, feed deprivation, dehydration, muscle activity and damage and then analysed their association with meat quality and carcass yield traits. Finally, the impact of genetic selection for increased carcass yield on the metabolic response to feed deprivation was examined under resting and commercial slaughter conditions. This study utilised 2877 lambs of the Meat and Livestock Australia genetic resource flock from sites in Katanning, Western Australia and Armidale, New South Wales over a two year period. Production factors including site, year and kill group had the largest impact on all stress indicators at slaughter, the majority of which were elevated above normal range at slaughter. There was also considerable variation in the concentration of many indicators (particularly those reflecting fat turnover) which are likely to reflect differences in pre-slaughter management, on-farm nutrition, feed and water deprivation and various acute stressors. In addition, levels of metabolic indicators at slaughter were found to relate to lamb carcass phenotype, with leaner lambs demonstrating greater fat mobilisation and lower rates of glycogen turnover at slaughter. Similarly, site, year and kill group had the largest impact on ultimate pH, Warner-Bratzler shear force (WBSF) and carcass yield parameters in lamb. Importantly, ultimate pH in lamb loin was positively associated with slaughter levels of plasma glucose and lactate, indicating that acute pre-slaughter stress has an impact on glycogen turnover and increases ultimate pH in lamb. There was also a positive association between WBSF and kill-order, suggesting that lambs killed later within a kill group may have a greater duration of exposure to stress underpinning the link between kill-order, acute stress and the resultant decrease in WBSF tenderness. Feed deprivation up to 48 hours under resting conditions resulted in lower glucose concentrations and a greater non-esterified fatty acid (NEFA) and β-hydroxybutyrate (BHOB) response in Merino sired lambs compared to Terminal sired lambs. Selection for increased genetic growth and leanness also altered the NEFA, BHOB and glucose response to feed deprivation. Feed deprivation up to 48 hours under commercial slaughter conditions elicited a similar response, demonstrating that adipose tissue is highly sensitive to feed deprivation and stress in Merino genotypes. An important finding was that the NEFA response to feed deprivation was up to 35% higher under commercial slaughter conditions, highlighting that acute stress is a large driver of fat turnover in the pre-slaughter period. Feed deprivation did not affect loin ultimate pH, loin intramuscular fat content or tenderness but had a negative impact on ultimate pH of the M. semitendinosus in Merino lambs. Feed deprivation beyond 36hrs was also found to cause a 3% loss in carcass weight in both Merino and Terminal sired lambs, which on an industry level, could affect the profitability of lamb producers and processors. Further work is required to understand methods of mitigating acute pre-slaughter stress in order to minimise high ultimate pH and reduced tenderness. In addition, it was demonstrated that Merino genotypes have a significantly higher fat turnover in response to feed deprivation and stress. This indicates that a shorter duration of curfew and lairage may minimise carcass losses and improve meat quality.

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Foi avaliada a qualidade dos cortes cárneos contrafilé (Longissimus dorsi), picanha (Biceps femoris), coração da paleta (Triceps brachii) e filé-mignon (Psoas major), provenientes de cordeiros terminados em confinamento. As carnes foram embaladas a vácuo e, em seguida, analisadas após 30 horas (carne refrigerada a 6°C) do abate e maturadas (2 ?C) por 3, 7 e 14 dias. Foram realizadas análises qualitativas da carne, determinando-se pH, cor, oxidação lipídica, capacidade de retenção de água, força de cisalhamento, exsudato, perda por gotejamento, evaporação e cocção; também foi realizada análise sensorial da carne in natura, maturada por 3 e 7 dias. O delineamento experimental da análise sensorial foi o inteiramente casualizado, tendo 4 tratamentos (Longissimus dorsi, Biceps femoris, Triceps brachii e Psoas major) e 30 repetições (provadores); nas demais análises, o delineamento foi também o inteiramente casualizado, tendo 4 tratamentos constituídos por carne in natura, maturada por 3, 7 e 14 dias, com 8 repetições por tratamento. A coloração das carnes apresentou alterações, evidenciando-se tonalidade alaranjada e escurecimento com a maturação. A quantidade de exsudato presente na embalagem aumentou com a maturação; as perdas apresentaram diferenças com a maturação, tendo o valor menor no nono dia, 30,53 e 33,58, respectivamente, por evaporação e cocção. A menor capacidade de retencão de água foi 57,60, no oitavo dia. A maturação promoveu aumento da maciez; a máxima maciez foi obtida na carne maturada por 14 dias, 4,32 kgf/cm 2 . Os valores de pH e oxidação lipídica encontrados estão em acordo com o preconizado na literatura; respectivamente, sendo o máximo de 5,69, no quarto dia, e 0,29 mg malonaldeído/kg de amostra, no nono dia. Qualquer alteração relativa à cor da carne é indesejável, podendo acarretar prejuízos à comercialização, pois, a ...
It was evaluated the quality of sirloin (Longissimus dorsi), top sirloin cap (Biceps femoris), heart of beef shoulder (Triceps brachii) and tenderloin (Psoas major) cuts from lambs treated in feedlot. The meat was vacuous packed and analyzed after 30 hours from the slaughter (meat refrigerated at 6o C) and maturation (2o C) for 3, 7 and 14 days. Qualitative meat analysis were made determining the pH, color, lipid oxidation, water retain capacity, power of shearing stress, exudate, drip loss, evaporation and cooking; sensorial analysis in natura meat matured for 3 and 7 days were also made. The experimental design of sensory analysis was totally randomized, were made with 4 treatments (Longissimus dorsi, Biceps femoris, Tríceps brachii and Psoas major) and 30 repetitions (tasters); the other analyses the design in totally randomized with 4 treatments with in natura meat, matured for 3, 7 and 14 days, with 8 repetitions per treatment. The meat coloring alternated, all of them presented orange hue and darkening after matured. The quantity of exudate in the package raises in the maturation process. The losses presented difference in the maturation, the lower value was on the ninth day, 30.53 and 33.58 for evaporation and cooking respectively. The lower capacity of water retain was 57.60 on the eighth day. The maturation increased the softness, the maximun level was obtained in the meat matured for 14 days, 4.32 kgf/cm. The pH values and lipid oxidation identified are according to the recommended ones in the literature, the maximum was 5.69 on the fourth day and 0.29 mg of the malonaldehyde/kg sample on the ninth day. The undesirable modification on the color of the meat may not be good for the commercialization because it is one of the requirements analyzed by the consumers when they buy it. The loss of meat liquid is also undesirable because it reduces the weight of the meat; as it is ...

Orientador: Américo Garcia da Silva Sobrinho
Banca: Emanuel Almeida de Oliveira
Banca: Iraides Ferreira Furusho Garcia
Resumo: Objetivou-se avaliar as características da carcaça e de seus não componentes em cordeiros alimentados com fenode amoreira (FA) no concentrado em substituiçãoao farelo desoja e milho,além das características qualitativas de hambúrguerese linguiças elaboradas com fígadoovino. Foram utilizados 24 cordeiros com 15,48 ±0,07 kg de peso corporal alojados em baias individuais eabatidos aos 32,20 ± 0,49 kg. Os tratamentos foram: 0%FA: cana forrageira + concentrado, 12,5%FA: cana forrageira + concentrado + 12,5% defeno de amoreira na MS e 25%FA: cana forrageira + concentrado + 25%de feno de amoreirana MS. Os hambúrgueres e linguiças foram elaborados com carne de cordeiros provenientes do tratamento controle do experimento acima anterior, sem ou com (15 e 30%) inclusãode fígado ovino em substituição à carne de pescoços e costelas desossadas. Odelineamento experimental foi o inteiramente casualizadosendo os dados submetidos à análise de variância e regressãopelo programa estatístico Sisvar a 5% de significância.A inclusão do fenodeamoreira promoveu efeito linearcrescente para a profundidade do tórax, índice de musculosidade da perna e relaçãomúsculo:osso eefeito linear decrescente, para o índice de compacidade da carcaça,peso da paleta, área de olho de lombo obtida pelo ultrassom, peso e comprimento do fêmur, peso dapele e pesoe porcentagemdas extremidades dos membros. Houve efeito linear crescentepara teoresde sódio no fígado, potássio no coração e sódio, potássio, cálcio, ferro e cobre na língua de cordeiros recebendo feno de amoreira.A inclusão do fígado nos processados comcarne ovina promoveu aumento na luminosidade e efeitoquadrático para a intensidade de vermelho. As variáveis pH, capacidadede retenção de água, força de cisalhamento, oxidação lipídica no dia 0 e 45 dias, teor de gordura e sabor dos hambúrgueres tiveram efeito quadrático...
Abstract: The aim of this study was to evaluate non-components and carcass traits of lambs fed concentrate containing mulberry hay (FA) as a substitute for soybean and corn. Further, qualitative traits of hamburgers and sausages made with sheep liver were evaluated. Twenty-four lambs with 15.48 ± 0.07 kg live weight were allotted in individual pens and slaughtered at 32.20 ± 0.49 kg. The treatments were: 0%FA: sugarcane forage + concentrate, 12.5%FA: sugarcane forage + concentrate + 12.5% mulberry hay, dry basis and 25%FA: sugarcane forage + concentrate + 25% mulberry hay, dry basis. The hamburgers and sausages were elaborated with lamb meat from the control treatment of the experiment cited above, with the inclusion (15 and 30%) or not of sheep liver as a substitute for neck and ribs. A completely randomized design was used and data were submitted to an analysis of variance and regression analysis using the Sisvar software with a 5% significance level. A linearly increasing for chest depth, leg muscularity and muscle: bone ratio were observed with the inclusion of mulberry hay and a linearly decreasing for carcass compactness index, palette weight, loin-eye area through ultrasound, femur weight and length, skin weight and limb percentages. A linearly increasing effect for sodium levels in the liver, potassium in the heart and sodium, potassium, iron and cupper in the tongue were observed in the lambs fed mulberry hay. An increasing luminosity and a quadratic effect for red intensity were observed with the inclusion of liver in the meat products of sheep meat. The pH, water-holding capacity, shear force, lipid oxidation at 0 and 45 days, fat level and the flavor of hamburgers showed quadratic effects...
Mestre

One of the main drivers influencing consumers in the purchasing of red meat is the level of visible fat, and this is particularly important in lamb, with lamb often being perceived as fatty. Consumer-driven preference for leaner meat, coupled with the meat processing industries preference for a reduction in carcass fat, increasing lean meat yield and reducing waste, have led to continued selection for lean growth and reduced fatness in several meat producing species The perception of lamb being fatty could be directly targeted in isolation by reducing overall fat levels, however there are related effects on meat (eating) quality, and the combined improvement and consistency of meat (eating) quality and the reduction of overall fatness is more complicated. It is apparent that fat content plays a significant role in meat (eating) quality. Generally four major fat depots are recognised in animal carcasses, these are: subcutaneous (under the skin); internal organ associated; intermuscular (between muscles and surrounding muscle groups); and intramuscular (marbling, between muscle fibres), the latter generally regarded as having the greatest association with meat (eating) quality. X-ray computed tomography (CT) can measure fat, muscle and bone in vivo in sheep and CT predictions of carcass composition have been used in commercial UK sheep breeding programmes over the last two decades. Together with ultrasound measures of fat and muscle depth in the loin region, CT measured carcass fat and muscle weights have contributed much to the success of breeding for leaner carcasses and increased lean meat yield. Recently it has also been considered that x-ray computed tomography provides the means to simultaneously estimate IMF and carcass fat in vivo. Thus the aim of this project is to investigate the use of two and three-dimensional x-ray computed tomography techniques in the estimation of meat (eating) quality traits in sheep, and to further investigate the genetic basis of these traits and the possibility of their inclusion into current breeding programmes. The primary approach was the use of two-dimensional x-ray computed tomography, determining the most accurate combination of variables to predict IMF and mechanical shear force in the loin. The prediction of mechanical shear force was poor with accuracies ranging from Adj R2 0.03 – 0.14, however the prediction of IMF in the loin was more promising. CT predicted carcass fat weight accounted for a moderate amount of variation in IMF (R2 =0.51). These accuracies were significantly improved upon by including other information from the CT scans (i.e. fat and muscle densities, Adj R2 >0.65). Average muscle density in a single or multiple scans accounted for a moderate amount of the variation in IMF (Adj R2 = 0.51-0.60), and again accuracies R2 >0.65 were achieved, independent of CT-measured fat areas or predicted fat weights. Similar results were achieved with the use of three-dimensional CT scanning techniques (Adj R2 0.51 – 0.71), however, there was a dramatically increased requirement for image analysis when compared to two-dimensional techniques, and the increase in accuracy was not significant. This suggests that the current method of two-dimensional image capture is sufficient in the estimation of IMF in vivo in sheep. The prediction equations developed as part of this work were applied across divergent breed types (Texel, Scottish Blackface and Texel cross mule), to investigate the transferability of the prediction equations directly across to other breeds of sheep. As part of this study, the IMF levels across the breed types and sexes were also compared and found that IMF was significantly affected by breed type (P<0.001) with Scottish Blackface lambs having higher levels of IMF when compared to Texel cross mule lambs, and the lowest levels of IMF were in the purebred Texel lambs at the same liveweight or similar levels of carcass fatness. Sex also had a significant effect on IMF across breeds (P<0.001) with females having higher levels of IMF at similar levels of both carcass fat and liveweight, and within breed, females had significantly higher levels of IMF in both the purebred Texel and Scottish Blackface lambs, when compared at similar levels of carcass fat and liveweight (P<0.05). Using the models previously developed in purebred Texel to predict IMF in the Scottish Blackface and Texel cross mule, accuracies were found to be R2 = 0.57 – 0.64 and R2 = 0.37 – 0.38 respectively. Providing evidence that the equations are transferable across to some breeds more successfully than others, however, given that there is currently no method of accurately estimating IMF in vivo, accuracies across to both breeds are acceptable. The genetic parameter estimation was unsuccessful using the same research-derived dataset as previously employed in the study. However the ambition was always to investigate the genetic relationships between traits in a large industry dataset, exploiting the wealth of commercial CT information available. These investigations were considerably more successful, and among the first to present genetic parameters of novel CT-derived IMF estimates. The results found moderate heritability estimates of h2 0.31 and 0.36 for the final selected prediction equations, with clear indications that one model not including CT predicted carcass fat or any other fat measures, was more independent of these measures and the two separate prediction methods were highly genetically correlated with each other (rg = 0.89). The results from this study show that not only is it possible to accurately estimate IMF levels in the loin of Texel sheep using CT scanning, but that, until breed specific predictions are developed, the methods developed in this study are transferable across some breed types. The results also show that CT predicted IMF is heritable, independent of overall fatness and has the potential to be included in current breeding programmes. These findings can now be used to develop breeding programmes which enable breeders to make the best use of CT scanning technology to improve carcass composition while maintaining or possibly improving aspects of meat (eating) quality.

The typical South African red meat consumer is spoilt for choice when it comes to the selection of their Saturday braai staples – chops, steak and “boerewors”. Labels (primary information) claiming the meat is Free-Range, Natural, Region-of-Origin or simply a Generic product might cause some uncertainty when all that a consumer wants is a good-looking T-bone. The 2017/18 outbreak of listeriosis in South Africa, along with the previous meat scandals of undeclared meat-based ingredients, is undeniably a significant cause of concern to South African meat producers and consumers. The absence of or incomplete product information in the agricultural and food markets have consumers asking more questions about what is in their meat. This gap in information about the effect of secondary information as a supplement to the labelled (primary source) information became the premise for this study. The effect of information on consumers’ demand has been studied across the globe. On the other hand, little research has been done in a South African context, which only focuses on the effect of positive secondary information on consumers’ purchasing decisions and ultimately their willingness to pay (WTP) for fresh meat’s quality cues and attributes. This study is concerned with examining if and how positive secondary information about differentiated fresh lamb meat products will have an impact on consumers’ willingness to pay. The WTP was elicited through an experimental auction, and the results could potentially be used to help realign the marketing approaches of the industry. The analysis is based on 51 respondents participating in a two-stage experimental auction, three months apart. A random nth-price auction was used to obtain the willingness to pay estimates. During the first stage, a pre-auction survey was done to define the exact demographic structure of the samples as well as gaining an understanding of the sample’s purchasing and consumption behaviour. The first auction sets measured the initial willingness to pay (based on prior knowledge and beliefs) and the immediate effect of positive secondary information on the consumers’ willingness to pay. In the second stage (3 months after the first auction), the willingness to pay values were re-elicited for the same group of participants and products, but this time without providing any positive secondary information. The second stage was conducted to determine the long-term effect of positive secondary information on the participants’ willingness to pay. The results from the experimental auction showed that the provision of positive secondary information is useful and has a positive effect on the consumers’ willingness to pay Free-Range, Natural and Region-of-Origin fresh lamb meat products. In the long-term, the average willingness to pay bids increased after the positive secondary information was presented to the participants.
Dissertation (MSc)--University of Pretoria, 2018.
Agricultural Economics, Extension and Rural Development
MSc
Unrestricted

Orientador: Rafael Silvio Bonilha Pinheiro
Co-orientador: Heloiza Ferreira Alves do Prado
Banca: Antonio Carlos Homem Junior
Banca: Nivea Maria Brancacci Lopes Zeola
Resumo: Foi avaliada a qualidade dos cortes cárneos contrafilé (Longissimus dorsi), picanha (Biceps femoris), coração da paleta (Triceps brachii) e filé-mignon (Psoas major), provenientes de cordeiros terminados em confinamento. As carnes foram embaladas a vácuo e, em seguida, analisadas após 30 horas (carne refrigerada a 6°C) do abate e maturadas (2 ̊C) por 3, 7 e 14 dias. Foram realizadas análises qualitativas da carne, determinando-se pH, cor, oxidação lipídica, capacidade de retenção de água, força de cisalhamento, exsudato, perda por gotejamento, evaporação e cocção; também foi realizada análise sensorial da carne in natura, maturada por 3 e 7 dias. O delineamento experimental da análise sensorial foi o inteiramente casualizado, tendo 4 tratamentos (Longissimus dorsi, Biceps femoris, Triceps brachii e Psoas major) e 30 repetições (provadores); nas demais análises, o delineamento foi também o inteiramente casualizado, tendo 4 tratamentos constituídos por carne in natura, maturada por 3, 7 e 14 dias, com 8 repetições por tratamento. A coloração das carnes apresentou alterações, evidenciando-se tonalidade alaranjada e escurecimento com a maturação. A quantidade de exsudato presente na embalagem aumentou com a maturação; as perdas apresentaram diferenças com a maturação, tendo o valor menor no nono dia, 30,53 e 33,58, respectivamente, por evaporação e cocção. A menor capacidade de retencão de água foi 57,60, no oitavo dia. A maturação promoveu aumento da maciez; a máxima maciez foi obtida na carne maturada por 14 dias, 4,32 kgf/cm 2 . Os valores de pH e oxidação lipídica encontrados estão em acordo com o preconizado na literatura; respectivamente, sendo o máximo de 5,69, no quarto dia, e 0,29 mg malonaldeído/kg de amostra, no nono dia. Qualquer alteração relativa à cor da carne é indesejável, podendo acarretar prejuízos à comercialização, pois, a ...
Abstract: It was evaluated the quality of sirloin (Longissimus dorsi), top sirloin cap (Biceps femoris), heart of beef shoulder (Triceps brachii) and tenderloin (Psoas major) cuts from lambs treated in feedlot. The meat was vacuous packed and analyzed after 30 hours from the slaughter (meat refrigerated at 6o C) and maturation (2o C) for 3, 7 and 14 days. Qualitative meat analysis were made determining the pH, color, lipid oxidation, water retain capacity, power of shearing stress, exudate, drip loss, evaporation and cooking; sensorial analysis in natura meat matured for 3 and 7 days were also made. The experimental design of sensory analysis was totally randomized, were made with 4 treatments (Longissimus dorsi, Biceps femoris, Tríceps brachii and Psoas major) and 30 repetitions (tasters); the other analyses the design in totally randomized with 4 treatments with in natura meat, matured for 3, 7 and 14 days, with 8 repetitions per treatment. The meat coloring alternated, all of them presented orange hue and darkening after matured. The quantity of exudate in the package raises in the maturation process. The losses presented difference in the maturation, the lower value was on the ninth day, 30.53 and 33.58 for evaporation and cooking respectively. The lower capacity of water retain was 57.60 on the eighth day. The maturation increased the softness, the maximun level was obtained in the meat matured for 14 days, 4.32 kgf/cm. The pH values and lipid oxidation identified are according to the recommended ones in the literature, the maximum was 5.69 on the fourth day and 0.29 mg of the malonaldehyde/kg sample on the ninth day. The undesirable modification on the color of the meat may not be good for the commercialization because it is one of the requirements analyzed by the consumers when they buy it. The loss of meat liquid is also undesirable because it reduces the weight of the meat; as it is ...
Mestre

Thesis (MScAgric)--Stellenbosch University, 2008.
ENGLISH ABSTRACT: The aim of this study was to investigate the effect of South African production system (feedlot {FL-} or free-range {FR-}) and gender (ewes, rams or castrates) on growth and carcass characteristics of Dorper sheep. Male lambs (castrates and rams) grew twice as fast as ewes (P<0.05) under FL-conditions while much smaller differences were observed between gender groups in FR-lambs. FL-lambs produced heavier carcasses (P=0.0003) with higher dressing percentages (P<0.05) and greater carcass fatness levels (P<0.052) than FR- lambs. No differences attributable to production system were found on meat tenderness (as indicated by Warner Bratzler shear force strength) and on the intramuscular lipid concentration. In contrast, sensory evaluation results suggested that meat from FL-lambs was juicier and more tender than meat from FR-lambs. The sensory panel could not distinguish between FL and FR meat as far as the attributes of aroma and flavour were concerned. Cholesterol results indicated that for intermuscular fat, higher cholesterol levels were observed for FL-lambs than for FR-lambs. The level of palmitic acid (C16:0) was significantly higher (P=0.0375) in the Longissimus dorsi (LD) muscles of FL-lambs. For intramuscular fat from the Biceps femoris (BF) muscle, g-linolenic acid (C18:3n-6) was higher (P<0.0001) in FL- lambs. Results for intramuscular BF further indicated that ram lambs had the highest (P=0.0019) palmitic acid (C16:0) and sum of TUFA (P=0.0014), castrates had the highest (P=0.0260) α-linolenic acid (C18:3n-3) and g-linolenic acid (C18:3n-6), while ewe lambs had the highest (P=0.0014) SFA concentrations. Linoleic acid (C18:2n-6c) was significantly higher (P=0.0067) in the subcutaneous fat of FL-lambs while FR-lambs had more linolenic acid (C18:3n-3). For the kidney fat, FR-feeding increased (P < 0.05) stearic (C18:0), linolelaidic (C18:2n-6t), α-linolenic (C18:3n-3) and homo-g-linolenic acid (C20:3n-6) percentages. Conversely, linoleic acid (C18:2n-6c) was increased (P=0.0372) by FL-feeding. For the intermuscular fat, FR-lambs had higher linolenic acid (C18:3n-3) and SFA (P=0.0113 and P=0.0341) compared to FL-lambs. On the other hand, the sum of TUFA for the intermuscular fat was higher (P=0.0341) in FL-lambs compared to FR-lambs. Results from the study imply that the consumer may not necessarily be able to discern between meat from FR- or FL-lambs, although they may possibly discriminate against the increase in visible fatness of FL-lambs. No clear advantage of production system in terms of human health could be demonstrated as far as the proximate chemical composition and the fatty acid composition of the meat was concerned. The faster growth and the associated shorter production cycle of FL-lambs could be an advantage under certain production systems. However, it needs to be weighed against the cost of concentrate feeding and the preference consumers are likely to develop for lamb produced in natural environments.
AFRIKAANSE OPSOMMING: Die doel van die studie was om Suid Afrikaanse produksiestelsel (voerkraal {VK-} of veld {VD}) en geslag (ooie, hamels of ramme) op die groeivermoë en karkaseienskappe van die Dorperskape te bepaal. Manlike lammers (ramme and hamels) het twee keer vinniger (P<0.05) as ooilammers onder VK-toestande gegroei, terwyl kleiner verskille tussen geslagsgroepe by VD-diere waargeneem is. VK-lammers het swaarder karkasse (P=0.0003), hoër uitslagpersentasies (P<0.05) en meer karkas vet (P<0.052) as VD -lammers vertoon. Geen verskille as gevolg van produksiestelsel is op die sagtheid van vleis (soos aangedui deur Warner-Bratzler skeurkragwaardes) en die binnespierse vetinhoud gevind nie. Daarenteen het sensoriese analises aangedui dat vleis van VK-lammers sappiger en sagter as vleis van VD- lammers was. Die sensoriese paneel kon nie verskille aangaande die aroma en geur van vleis tussen VK- en VD-vleis onderskei nie. Cholesterolvlakke was hoër vir VK-lammers as by VD-lammers. Die vlak van palmitiese suur (C16:0) was hoër (P=0.0375) in die Longissimus dorsi (LD) spier van VK-lammers. Vir binnespierse vet van die Biceps femoris (BF) spier was g-linoleniese suur (C18:3n-6) hoër (P<0.0001) in VK-lammers. Resultate vir binnespierse vet van die BF spier het verder bewys dat ramlammers die hoogste (P=0.0019) palmitiese suur (C16:0) and totale onversadigde vetsure (P = 0.0014) getoon het, hamels die hoogste (P=0.0260) α-linoleniese suur (C18:3n-3) en g-linolenese suur (C18:3n-6) getoon het terwyl ooilammers die hoogste (P=0.0014) versadigde vetsuurvlakke getoon het. Linoliese suur (C18:2n-6c) was hoër (P=0.0067) in die onderhuidse vet van VK-lammers terwyl VD-lammers meer linoliese suur (C18:3n-3) gehad het. Resultate vir niervet het getoon dat VD-voeding die persentasies van steariese (C18:0), linoleladiese (C18:2n-6t), α-linoleniese (C18:3n-3) and homo-g-linoleniese suur (C20:3n-6) verhoog (P<0.05) het relatief tot VK-voeding. Linoliese suur (C18:2n-6c) is deur VK-voeding verhoog (P=0.0372). Vir intermuskulêre vet het VD-lammers hoër linoleniese suur (C18:3n-3) en versadigde vetsure (P=0.0113 en P=0.0341) as VK-lammers gehad. Die totale onversadigde vetsure vir tussenspiere vet was hoër (P=0.0341) in VK-lammers in vergelyking met VD-lammers. Resultate van hierdie studie dui daarop dat verbruikers nie noodwendig tussen vleis van VD- en VK-lammers sal onderskei nie, alhoewel hulle dalk teen die sigbaar vetter vleis van VK-lammers kan diskrimineer. Geen definitiewe voordeel in terme van menslike gesondheid kon op grond van die chemiese samestelling van die vleis bevestig word nie. Vinniger groei van VK-lammers, en die korter produksiesiklus wat daarmee verband hou, mag onder sekere produksie stelsels ʼn voordeel wees. Die voordeel moet teen die hoër koste van VK-voeding en die voorkeur van verbruikers vir lam produksie in natuurlike omgewing opgeweeg word.

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Este trabalho teve como objetivo avaliar aspectos qualitativos da carne de cordeiros in natura, relacionados ao pH, cor, maciez, capacidade de retenção de água, perdas de peso por cocção, composição centesimal, colesterol, perfil de ácidos graxos e concentração de vitamina E (α-tocoferol), assim como a qualidade sensorial de hambúrguer e linguiça provenientes dos cortes menos nobres da carcaça de cordeiros Ile de France. O experimento foi desenvolvido na Faculdade de Ciências Agrárias e Veterinárias (FCAV) da Universidade Estadual Paulista (Unesp), Câmpus de Jaboticabal, SP. Foram avaliados 32 cordeiros Ile de France, machos não castrados, dos 15 aos 32 kg ± 200g de peso corporal, que foram divididos nos seguintes tratamentos: C – cana-de-açúcar (var. IAC 86-2480) + concentrado; CG – cana-de-açúcar + concentrado com grãos de girassol; CE – cana-de-açúcar + concentrado com 1000 mg vitamina E/kg de matéria seca (MS) da dieta; CGE – cana-de-açúcar + concentrado com grãos de girassol e 1000 mg vitamina E/kg de MS da dieta. O delineamento experimental foi o inteiramente casualizado em esquema fatorial 2 x 2 (com ou sem grãos de girassol e com ou sem 1000 mg de vitamina E/Kg de MS da dieta). Para a análise sensorial da carne ovina o delineamento experimental utilizado foi o inteiramente casualizado, com 2 tratamentos (sem grãos de girassol e sem vitamina E e com grãos de girassol e vitamina E). A carne dos animais que foram alimentados com grãos de girassol teve menor a* (intensidade de vermelho) e oxidação lipídica e a carne dos que receberam grãos de girassol e vitamina E teve maior concentração de vitamina E. A dieta não influenciou na composição centesimal e na análise sensorial da carne. A inclusão dos grãos de girassol melhorou o perfil de ácidos graxos aumentando a quantidade do ácido vacênico, do linoleico...
The aim of this study was to evaluate the pH, color, tenderness, water retention capacity, cooking loss, chemical composition, cholesterol, fatty acid profile and the concentration of vitamin E (α-tocopherol), as well as the sensory analysis of hamburger and sausage from the less noble cuts of carcasses of Ile de France lambs. The experiment was conducted at the College of Agriculture and Veterinary Sciences (FCAV), Universidade Estadual Paulista (Unesp), Jaboticabal, SP. Thirty two Ile de France lambs were evaluated, non-castrated males, with an average of body weight from15 to 32 kg ± 200 g. The animals were divided into the following treatments: S – sugarcane (var. IAC 86-2480) + concentrate; SS - sugarcane + concentrate with sunflower seeds; SE - sugarcane + concentrate with 1000 mg vitamin E/kg of dry matter (DM) of the diet; SSE - sugarcane + concentrate with sunflower seeds and 1000 mg vitamin E/kg of DM of the diet. A completely randomized design was used, in a factorial scheme 2x2 (with or without sunflower seeds and with or without 1000mg vitamin E/kg of DM of the diet). A completely randomized design was used for the sensory analysis of the meat composed by 2 treatments (without sunflower seeds and vitamin E and with sunflower seeds and vitamin E). Meat from animals that were fed sunflower seeds had lower a* (redness) and lipid oxidation and the meat form animals that received sunflower seeds and vitamin E had a higher concentration of vitamin E. The diet did not affect the chemical composition and sensory evaluation of meat. The inclusion of sunflower seeds improved fatty acid profile by increasing the amount of vaccenic acid, linoleic and the conjugated linoleic acid (CLA). The hamburgers from meat of animals fed sunflower seeds and vitamin E had lower shear force and lipid oxidation... (Complete abstract click electronic access below)

The potential of red meat, particularly that produced from grass-fed animals, to contribute to dietary intakes of long chain (LC) n-3 PUF A has become the focus of recent research. However, there remains little information on precise quantities of these fatty acids found in commercially produced red meat, the use of grass finishing diets by producers, or the ability of red meat produced from grass feeding regimes to contribute to LCn-3 PUF A intakes or status in consumers, especially in the UK and Ireland. Extensive fatty acid data were measured for beef and lamb produced in Northern Ireland over a 12 month period and the frequency of a grass diet being offered to animals before slaughter was determined by a survey carried out among a sample of beef and lamb producers. To investigate the effect of consumption of red meat produced from grass-fed animals on LCn-3 PUF A status, a human intervention study was carried out among healthy subjects. In addition, the potential for red meat produced from grass-fed animals to contribute to LCn-3 PUF A intakes in the Irish population was hypothetically assessed based on current intakes of meat. Beef and lamb were reported to contain concentrations ofLCn-3 PUFA similar to levels achieved with grass feeding by other studies. The season of slaughter and, to a lesser extent, the reported finishing diet of the animal were found to cause variation in concentrations ofLCn-3 PUFA and conjugated linoleic acids (CLA) found in beef and lamb. The survey revealed that grass finishing diets are commonly offered to animals by producers of beef and lamb, but the frequency of these diets also varied by season. In the human intervention study, consumption of red meat from grass-fed animals was associated with significantly increased plasma and platelet LCn-3 PUF A status among healthy subjects. Based on red meat consumed in the Irish diet being from grass-fed animals, the provision of red meat to LCn-3 PUF A intakes would be modestly increased than if meat consumed were from concentrate-fed animals. In conclusion, the production of red meat from grass-fed animals will contribute to increased LCn-3 PUF A intakes and status among Irish consumers, where red meat is habitually consumed. Further research is warranted to investigate the opportunity to further enhance concentrations ofLCn-3 PUF A within red meat by increased use of grass feeding regimes in beef and lamb production.

Orientador: Américo Garcia da Silva Sobrinho
Banca: Alda Lúcia Gomes Monteiro
Banca: Iraídes Ferreira Furucho Garcia
Banca: Gustavo Rezende Siqueira
Banca: Eliana Gertrudes Macedo Lemos
Resumo: Este trabalho teve como objetivo avaliar aspectos qualitativos da carne de cordeiros in natura, relacionados ao pH, cor, maciez, capacidade de retenção de água, perdas de peso por cocção, composição centesimal, colesterol, perfil de ácidos graxos e concentração de vitamina E (α-tocoferol), assim como a qualidade sensorial de hambúrguer e linguiça provenientes dos cortes menos nobres da carcaça de cordeiros Ile de France. O experimento foi desenvolvido na Faculdade de Ciências Agrárias e Veterinárias (FCAV) da Universidade Estadual Paulista (Unesp), Câmpus de Jaboticabal, SP. Foram avaliados 32 cordeiros Ile de France, machos não castrados, dos 15 aos 32 kg ± 200g de peso corporal, que foram divididos nos seguintes tratamentos: C - cana-de-açúcar (var. IAC 86-2480) + concentrado; CG - cana-de-açúcar + concentrado com grãos de girassol; CE - cana-de-açúcar + concentrado com 1000 mg vitamina E/kg de matéria seca (MS) da dieta; CGE - cana-de-açúcar + concentrado com grãos de girassol e 1000 mg vitamina E/kg de MS da dieta. O delineamento experimental foi o inteiramente casualizado em esquema fatorial 2 x 2 (com ou sem grãos de girassol e com ou sem 1000 mg de vitamina E/Kg de MS da dieta). Para a análise sensorial da carne ovina o delineamento experimental utilizado foi o inteiramente casualizado, com 2 tratamentos (sem grãos de girassol e sem vitamina E e com grãos de girassol e vitamina E). A carne dos animais que foram alimentados com grãos de girassol teve menor a* (intensidade de vermelho) e oxidação lipídica e a carne dos que receberam grãos de girassol e vitamina E teve maior concentração de vitamina E. A dieta não influenciou na composição centesimal e na análise sensorial da carne. A inclusão dos grãos de girassol melhorou o perfil de ácidos graxos aumentando a quantidade do ácido vacênico, do linoleico... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: The aim of this study was to evaluate the pH, color, tenderness, water retention capacity, cooking loss, chemical composition, cholesterol, fatty acid profile and the concentration of vitamin E (α-tocopherol), as well as the sensory analysis of hamburger and sausage from the less noble cuts of carcasses of Ile de France lambs. The experiment was conducted at the College of Agriculture and Veterinary Sciences (FCAV), Universidade Estadual Paulista (Unesp), Jaboticabal, SP. Thirty two Ile de France lambs were evaluated, non-castrated males, with an average of body weight from15 to 32 kg ± 200 g. The animals were divided into the following treatments: S - sugarcane (var. IAC 86-2480) + concentrate; SS - sugarcane + concentrate with sunflower seeds; SE - sugarcane + concentrate with 1000 mg vitamin E/kg of dry matter (DM) of the diet; SSE - sugarcane + concentrate with sunflower seeds and 1000 mg vitamin E/kg of DM of the diet. A completely randomized design was used, in a factorial scheme 2x2 (with or without sunflower seeds and with or without 1000mg vitamin E/kg of DM of the diet). A completely randomized design was used for the sensory analysis of the meat composed by 2 treatments (without sunflower seeds and vitamin E and with sunflower seeds and vitamin E). Meat from animals that were fed sunflower seeds had lower a* (redness) and lipid oxidation and the meat form animals that received sunflower seeds and vitamin E had a higher concentration of vitamin E. The diet did not affect the chemical composition and sensory evaluation of meat. The inclusion of sunflower seeds improved fatty acid profile by increasing the amount of vaccenic acid, linoleic and the conjugated linoleic acid (CLA). The hamburgers from meat of animals fed sunflower seeds and vitamin E had lower shear force and lipid oxidation... (Complete abstract click electronic access below)
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