Dissertations / Theses on the topic 'Sheep Lambs'

9 pp.
As a general rule, lambs are not purchased until they are at least 8 weeks old and exceed 40lbs. in weight. The lamb should gain an average of .5 to .8 lbs. a day. This publication discusses how to feed a show lamb according to its nutrient needs.

Bibliography: leaves 281-316. Presents investigations on pubertal development in South Australian merino ram lambs and examines the effect of active and passive immunizations against oestradiol-17ℓ or oestrone on testicular maturation.

Five hundred, ninety-seven and 643 white face range ewes were used in a 2 year study, respectively, in a 3-way factorial arrangement to determine effect of supplemental linoleic oil on lamb serum metabolites, thermogenesis and lamb growth. During the last 45 ± 4 days of gestation ewes were group fed a daily supplement of either 0.23 kg•ewe-1•d-1 whole safflower seed (SS) or 0.34 kg•ewe-1•d-1 whole barley (C). Colostrum was collected from each supplement treatment and pooled according to treatment. At parturition, twin born lambs received either SS or C pooled colostrum. One h postpartum, lambs were placed in a 0°C dry cold chamber for 30 min. and lamb rectal temperature was recorded at one min intervals. Blood samples were taken prior to and after cold exposure. Lamb weights were taken at birth, turnout and weaning for growth. There was no difference (P > 0.10) in body temperatures between lambs born to ewes supplemented with SS vs. C or between lambs given pooled colostrum form SS or C supplemented ewes. At 0 minutes lambs born to SS supplemented ewes had lower glucose (P = 0.05), total protein (P = 0.05) and NEFA (P = 0.003) and higher BUN (P = 0.03) than lambs from C supplemented ewes. Lambs from SS supplemented ewes had lower NEFA (P = 0.01) after cold exposure (30 minutes). Total protein concentration was similar in year 1 but lower (P < 0.01) in year 2. Concentrations of aGP were higher in lambs from SS supplemented ewes at both 0 and 30 min in year 1. Lambs from SS ewes had higher (P < 0.01) blood aGP levels at both 0 and 30 min in year 1 than in year 2. No differences (P > 0.30) were detected between lambs from SS ewes vs. C for changes in any blood metabolites measured during cold stress period. No differences (P > 0.12) were detected for average date of birth, number of lambs born, number of lambs present at turnout and weaning or for weight of lambs at turnout or weaning for ewes receiving either SS or C supplements.

Includes bibliographical references (leaves 276-2970. Investigations presented involve 18 hour to 5 day old South Australian merino lambs. Some twin lambs were available for comparative studies. Examines the relationship between the strength of ewe-lamb bond and the lamb's ability to follow the mother, the energy availability and usage in the lamb, particularly for locomotion, and the metabolic and cardiorespiratory responses to locomotion.

Thesis (MScAgric)--Stellenbosch University, 2013.
ENGLISH ABSTRACT: The aim of the study was to determine the effect of increasing levels of Maize silage in finishing diets for Merino lambs on their feed intake, production performance, feed conversion ratio, digestibility and meat quality. Concerns exist regarding the intake of high moisture and fibre containing silage in sheep due to the physical fill effect thereof. To determine the efficiency of silage as feed ingredient for sheep, maize was cut at 27% dry matter (DM), compacted into 220 litre plastic drums, sealed and left to ferment for 60 days. The silage produced was analysed for fermentation end products and the nutritive value determined. The silage produced had an optimum pH, starch and water soluble carbohydrate (WSC) content. The crude protein (CP) content (112.2 g/kg DM) was higher than expected. Four diets containing, on a dry matter (DM) basis either, 0, 20, 50 or 70% maize silage was formulated on an iso-nutrient basis with exception of neutral detergent fibre (NDF). The aim was to establish the effect of increasing levels of silage on animal production with regard to dry matter intake, growth, digestibility and meat quality. Diets were formulated on an iso-nutrient basis to match the 70% silage diet and therefore had relatively low specifications due to the high inclusion of silage from the 70% silage diet. A growth study and an in vivo and in vitro digestibility study were conducted to determine the effect of the different diets on feedlot sheep production. Meat quality was also determined to establish whether the experimental diets had an effect on meat quality. Forty lambs in a completely randomised block design, with four treatments, were used in a 60-day finishing study. The dry matter intake (DMI) of lambs decreased as silage inclusion increased above the 20% silage inclusion level. At the 20% inclusion rate, the feed intake of the animals was stimulated. This resulted in significant differences found between the cumulative intake of the low and the high silage diets. Feed conversion ratio (FCR) was poorer, however, for the control and 20% silage diets. The poor FCR most likely was related to the quality of the feed ingredients used in the formulation of the control feed and the concentrate in the 20% silage diet rather than the silage itself. Significant differences were also found in the dressing percentage of the slaughtered animals where the 20 and 50% silage diets had a higher dressing percentage than the control and 70% silage diets. It was concluded that silage can be successfully incorporated into sheep diets, especially at low levels where its inclusion stimulates intake. Eight animals per group were used in an in vivo digestibility study to determine the apparent digestibility of the experimental diets. Feed, faeces and urine samples collected during the trial period were analysed for the respective nutrients. The 20% diet, even though having the best overall apparent digestibility, did not result in better production responses. Lambs on the 20% silage diet had the highest daily DM intake, which resulted in them having the highest energy intake. There were no differences in total energy excreted between the silage-based diets. This resulted in the 20% silage diet also having the best energy retention. Nitrogen retention was the highest for the control and 20% silage diets. This can be ascribed to the low quality of the concentrate part of the diet. The 20% silage diet, as previously stated, had the highest apparent DM and organic matter (OM) digestibility, while the control diet showed the lowest overall nutrient digestibility. The low nutrient digestibility of the control diet can be ascribed to the relatively poor quality ingredients used. There were no differences in the crude protein (CP) digestibility between the control and the 20% diet. Both proved to be higher than the CP digestibility of the 50 and 70% silage diet. As the neutral detergent insoluble nitrogen (NDIN) was higher for the 50 and 70% diets, this observation was not surprising. Fibre content of the silage-based diets increased as the inclusion level of the silage increased, which resulted in a decrease in overall fibre digestion. Three cannulated sheep were adapted on each experimental diet for two weeks before rumen fluid was collected for the in vitro digestibility study. No differences between the silage based diets were found for in vitro true digestibility (IVTD). The IVTD of the 20, 50 and 70% diets were higher, however, than the IVTD of the control diet confirming earlier observations on the choice of ingredients used in the control diet to formulate iso-nutrient diets. Degradability coefficients were determined for the DM and NDF fractions of the different experimental diets and fitted to the non-linear model; p = a + b (1 – e-ct). The amount of DM that disappeared in a certain time (t) is represented by p. Constant a represents the fraction that was rapidly soluble, b represents the potential degradable fraction and c is the rate at which b was degraded. There were no differences between experimental diets for the rapidly soluble fraction. The silage-based diets had a higher potential degradable fraction (b) but did not differ in the degradability rate (c) from the control diet. Silage-based diets had higher overall effective degradability than the control but did not differ between one another. Constant a was not determined for NDF degradability since the NDF fraction did not have a rapidly soluble fraction. The control diet had the lowest potential degradable NDF fraction with the rate also being lower than the silage based diets. Effective NDF degradability was highest for the 50% silage diet. Lambs used in the finishing study were slaughtered and meat samples taken for meat quality tests. The pH, colour, drip loss, cooking loss, shear force and fatty acid composition were determined on the Longissimus dorsi samples collected at Roelcor (Malmesbury, Western Cape, South Africa). Proximate analysis was also conducted on the meat samples. The experimental diets did not have a significant effect on the proximate chemical composition of the meat. Colour differences were found; however no clear pattern could be established. There were no differences in fatty acid composition. It can be concluded that up to 70% maize silage can be included in the finishing diets of Merino lambs with no adverse effects on the meat quality. The study showed that 20% maize silage can be included in the finishing diets of Merino lambs without negatively affecting intake, production, digestibility or meat quality. Future research is needed to optimise the 20% silage diet, however, and to again look at the effect that it will have on animal production, including the effect thereof on total methane emissions.
AFRIKAANSE OPSOMMING: Die doel van die studie was om te bepaal of mielie kuilvoer doeltreffend gebruik kan word as ‘n komponent in die afronding van Merino lammers. Gedurende die proses is mielies gesny teen 27% droë materiaal (DM), en saamgepers in 220 liter plastiek dromme. Dit is toegelaat om te fermenter vir 60 dae. Die kuilvoer wat daaruit geproduseer is, is geanaliseer vir fermentasie eindprodukte, en die voedingstofwaarde is bepaal. Vier diëte met onderskeidelik 0 (kontrole), 20, 50 en 70% kuilvoer is geformuleer op ‘n iso-nutriëntbasis met die uitsondering van vesel (NDF). ‘n Groeistudie, tesame met ‘n in vivo en in vitro verteerbaarheidstudie is uitgevoer om die effek van die verskillende diëte op diere produksie te toets. Vleiskwaliteit toetse is ook gedoen om te kyk of die verskillende diëte ‘n effek op vleiskwaliteit het. Veertig lammers, in ‘n ewekeurige blokontwerp, is gebruik in ‘n 60 dae afrondingstudie. Dit is opgemerk dat die DM inname (DMI) afgeneem het soos die kuilvoer insluiting bo die 20% vlak toegneem het. By die 20% insluitingskoers, is voerinname by die diere gestimuleer. Dit het veroorsaak dat beduidende verskille gevind is tussen die kumulatiewe inname van die lae en die hoë kuilvoer diëte. Die voeromsetkoers (VOK) was egter hoër vir die kontrole en 20% kuilvoer diëte. Beduidende verskille is ook gevind in die uitslagpersentasie van die diere, waar die 20% en 50% kuilvoer diëte ‘n hoër uitslagpersentasie as die kontrole en 70% kuilvoer diëte gehad het. Agt diere is per groep gebruik in ‘n in vivo verteerbaarheidstudie om die skynbare verteerbaarheid van die eksperimentele diëte te toets. Voer, feses en urien monsters is gedurende die proefperiode ingesamel en geanaliseer. Die 20% kuilvoer dieet het die hoogste DM en organiese materiaal skynbare verteerbaarheid teenoor die kontrole diet wat die laagste gehad het. Daar was geen verskille in die ru- proteien (RP) verteerbaarheid van die kontrole en 20% kuilvoer diet nie. Beide was hoër as die RP verteerbaarheid van die 50% en 70% kuilvoer dieet. Die veselinhoud van die kuilvoergebasseerde diëte het toegeneem soos die insluitingsvlak van die kuilvoer toegeneem het, wat ‘n afname in veselvertering veroorsaak het. Lammers op die 20% kuilvoer dieet het die hoogste daaglikse DM inname gehad, wat die hoogste energie inname tot gevolg gehad het. Daar was geen verskille in die totale energie inname van die kuilvoergebasseerde diëte – dit het veroorsaak dat die 20% kuilvoer dieet ook die beste energie retensie gehad het. Stikstof retensie was die hoogste vir die kontrole en 20% kuilvoer dieet. Drie gekannuleerde skape is vir twee weke op elke eksperimentele dieet aangepas voordat rumenvloeistof ingesamel is vir die in vitro verteerbaarheidstudie. Geen verskille is gevind vir die in vitro ware verteerbaarheid (IVWV) tussen die kuilvoergebasseerde diëte nie. Hulle was egter hoër as die IVWV van die kontrole dieet. Degradeerbaarheid koëffisiënte is bepaal vir die DM en NDF fraksies van die verskillende eksperimentele diëte en is gepas in die model p = a + b (1 – e-ct). Die hoeveelheid DM wat verdwyn het binne ‘n sekere tyd (t) word voorgestel deur p. Die konstante a verteenwoordig die fraksie wat vinnig oplosbaar is, b verteenwoordig die potensieel degradeerbare fraksie en c is die koers waarteen b gedegradeer is. Konstante a is nie bepaal vir die NDF degradeerbaarheid nie, aangesien die NDF fraksie nie ‘n vinnig oplosbare fraksie gehad het nie. Daar was geen verskille in die vinnig oplosbare fraksie tussen eksperimentele diete nie. Kuilvoer gebasseerde diete het ‘n hoër potensieel degradeerbare fraksie gehad, maar daar was geen verskille in koers van degradering nie. Die kuilvoergebasseerde diëte het ‘n hoër DM effektiewe degradeerbaarheid as die kontrole dieet. Effektiewe NDF degradeerbaarheid was die hoogste vir die 50% kuilvoer dieet. Lammers in die studie gebruik is geslag en vleismonsters is geneem vir vleiskwaliteit toetse, insluitende pH, kleur, drupverlies, kookverlies en taaiheid. Proksimale analise is ook uitgevoer op die vleismonsters. Die eksperimentele diëte het nie ‘n beduidende effek op die proksimale chemiese samestelling van die vleis gehad nie. Kleur verskille is wel gevind, maar geen duidelike patroon kon vasgestel word nie. Daar was geen verskille in die vetsuur samestelling nie. Daar kan dus tot die gevolgtrekking gekom word dat mielie kuilvoer ingesluit kan word in die afrondingsdiëte van Merino lammers, tot by 70%, sonder enige negatiewe effekte op die vleiskwaliteit. Daar is tot die gevolgtrekking gekom dat mielie kuilvoer suksesvol geïnkorporeer kan word in skaapdiëte, veral teen lae vlakke (20%) waar die gebruik nie net inname stimuleer nie, maar ook geen negatiewe effekte het op produksie en verteerbaarheid nie.
Dr. Francois van de Vyver, Cape Wools and NWGA for providing funding in the form of post graduate bursaries

Spring-born ram lambs were used to examine: (1) sexual maturational changes in LH, FSH and prolactin (PRL) secretion, testicular gonadotropin receptors, and testicular size and function; (2) predictability of yearling ram reproductive function from juvenile testicular size and reproductive hormone measurements. Despite continuous increases in testis size, serum LH-profile characteristics became greatest between 2 and 4 months and declined thereafter. However, LH-peak frequency increased by about 2-fold between 6 and 7 months; this was associated with marked increases in testosterone (T) secretion and spermatogenic function. Mean FSH and PRL levels were maximum at 2 months and 3 to 5 months, respectively, and decreased thereafter. Increases in steroidogenic and spermatogenic function were due partly to increases in testicular content of LH and FSH receptors. Yearling ram testis size and spermatogenic function were predictable from testis size at 5 to 6 months, neonatal (50 days) secretion of LH and T, and pubertal (150 days) secretion of T. However, combinations of testicular size and reproductive hormone measurements provided greater predictive power.

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.

Ewes at two sites were fed to be either condition score 2 or 3 by Day 90 of pregnancy and then grazed on various levels of feed-on-offer (FOO) from Day 90 of pregnancy until weaning, to investigate whether nutrition of Merino ewes during pregnancy and lactation affected the muscle, fat and immunity to worms of their progeny. Eye muscle and fat depth at the C-site, and faecal worm egg counts (FWECs) of the progeny were measured between 7 - 27 months of age. Ewe condition score at day 90 of pregnancy did not impact largely on the eye muscle depth, fat depth or FWEC of the progeny. Increasing FOO available to ewes during the last 60 days of pregnancy and throughout lactation increased the eye muscle depth of progeny at one site and decreased the fat depth of progeny at the other site (P<0.05), but did not affect the majority of FWECs of the progeny at either site. The FWECs of the progeny were low, indicating a relatively low larval challenge, which limits the likelihood of differences in immunity to worms between the progeny being expressed. This Masters demonstrated that levels of nutrition available to Merino ewes typical of commercial grazing conditions had only small effects on the eye muscle and fat depth at the C-site, and on the faecal worm egg counts of their progeny

"April 2002" Bibliography: leaves 190-202. Examines the suitability of the [alpha] 2 adrenoreceptor agonist xylazine for providing safe and effective analgesia in 2 settings: for post-surgical pain in adult sheep used for biomedical research, and for routine husbandry procedures applied to lambs on farms, such as mulesing, tail-docking and castration. Concludes in setting 1 that intramuscular administration of xylazine was simple to perform yet was characterized by a rapid peak analgesic effect with a reasonable duration of action and minimal deleterious effects on cardiac output, blood pressure or arterial blood gases. In setting 2 the anti-nociceptive effects in lambs are of a similar magnitude and duration to those in adult sheep when the dose was scaled for body weight. A ranking of the relative painfulness of husbandry procedures was developed and used to assess the efficacy of intramuscular xylazine.

Thirty-seven Columbia and Cormo Crossbred July-weaned weather lambs were utilized in this study. A feeding trial was conducted to evaluate feed efficiency, average daily gain, feed cost per pound of gain, wool growth per day and per pound of grain, and average wool fiber diameter and distribution of fiber population of the wool. Lambs were raised to a uniform market weight of between 115 and 125 pounds and slaughtered to evaluate carcass weight, backfat thickness, loin eye area, internal body fat, leg circumference, dressing percentage, untrimmed wholesale cuts, trimmed retail cuts, and yield and quality grades. Suffok x Cormo/Rambouillet lambs were most efficient (P

Thesis (M. Tech.) - Central University of Technology, Free State, 2010
The objective of this research study was to quantify the differences in average daily gain (ADG), back fat thickness (BFT), eye muscle area (EMA), fat thickness (FT) on different body parts, the feed conversion ratio (FCR) and body dimensions (by means of body measurements) of Dorper lambs exposed to supplemented light. For this study 120 Dorper lambs (115 ± 10 days old) weighing (29.76 ± 5.01kg) were used. The lambs were randomly divided into three homogeneous groups (20 castrated and 20 intact males). The three groups were then exposed to different levels of supplemented light at 145 lux (16h, 24h and normal photoperiod). The animals were fed ad libitum with pellets containing 9.5 MJ ME/kg DM and 12% CP in open pens. The animals were weighed every 7 days while ultrasound scanning of the EMA and the BFT was done at the beginning and the end of the 35 day trial. The ADG, FCR and feed intake (FI) were calculated at the end of the trial. Linear body measurements including shoulder height, body length and heart girth were taken at day 1 and day 35 respectively. All the animals were slaughtered at the end of the trail. The carcasses were then weighed, graded and the FT was measured with a caliper. The final results of the study showed that no significant differences between the three treatment groups (consisting of wethers and rams) in terms of body measurements, ultrasound scanning ADG and FCR could be detected. However, a significant difference was found between the wethers and the rams in the whole trial for ADG. The ADG of the rams exposed to 16 hours of supplemented light was significantly better than the normal photoperiod and the 24 hour light supplementation group.

Antigen-specific and polyclonal serum immunoglobulin G (IgG) concentrations were measured in control (Con), vitamin A-deficient (A-def), and vitamin A-repleted (A-rep) lambs. In Trial, I ewe lambs were injected with primary and secondary antigenic challenges of ovalbumin (1mg) and lysozyme (.1mg). The A-def lambs were then repleted with vitamin A and all lambs were injected with primary and secondary antigenic challenges of human gamma globulin (HGG) (.1mg). In Trial II Con and A-def wether lambs were given primary and secondary antigenic challenges of ovalbumin (20μg). Half of the A-def lambs were then repleted with vitamin A. All lambs were subsequently given a primary and secondary challenge of HGG (20 μg). Spleen wt were similar for all treatments in Trial I while A-def V lambs in Trial II had greater spleen wt (P<.01) than Con or A-rep lambs. Polyclonal serum IgG concentrations were unaffected by treatment in Trial I while in Trial II concentrations were greater (P<.05) in the A-def lambs during the HGG challenge period. Antigen-specific IgG concentrations in both trials tended to be greater in the Con lambs towards the end of both the ovalbumin (Trial I and II) and lysozyme (Trial I) challenge periods. Control and A-rep lambs in Trial I responded similarly to the HGG challenges. In Trial II both the A-def and A-rep lambs had lower (P<.10) HGG specific serum IgG concentrations on the last 3 wk of the HGG challenge period as compared to A-def lambs. Humoral immune function appears to be impaired in A-def lambs and a 2-wk repletion period was not sufficient in this study to restore humoral immune function to normal levels.
Ph. D.

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.

Feeds often contain molybdenum (Mo) and sulfur (S) in excess of recommended allowances for adequate copper (Cu) absorption by ruminant livestock. Two randomized-block experiments were conducted using lambs given a cereal-based diet (90% of dry matter (DM) intake), containing 8 mg Cu, 0.7 mg Mo and 2.1g S per kg DM, that was either unsupplemented or supplemented with ammonium molybdate or sodium sulfate alone or in combination, to determine the effects of Mo, S and Mo+S on growth, hematology, serum Cu and Mo concentrations and reproductive function. Short term intake (4 weeks) by rams, aged 18 and 20 weeks, of 26 mg Mo alone or in combination with 2g S per kg DM, had no effect on growth, hematology or the concentration of total Cu in serum (TCu). However, supplemented groups had lower (P<0.05) concentrations of serum Cu soluble in trichloroacetic acid (TCA-Cu), but the group given Mo+S had the highest (P<0.05) concentration of serum residual Cu (RCu). Luteinizing hormone (LH) peak amplitude was affected by age*diet interaction (P<0.05), because of high amplitude LH peaks in the serum of lambs, aged 24 wks, given Mo alone. Testosterone serum secretory profiles did not differ among diet groups, but testosterone peak frequency was higher (P<0.05) for older ram lambs. Long term intake (32-39 wks) by ewe, ram and wether lambs (gonadal influence) of 12 mg Mo, or 2g S alone or combined per kg DM also had no effect on hematology or TCu. Food intake and liver weights were higher (P<0.05), but TCA-Cu was lower (P<0.05) for groups given S. Serum concentrations of total Mo (TMo) were higher (P<0.05) for Mo-supplemented groups, but RCu was highest only for the Mo+S group. Growth was affected by Mo*S*gonadal influence*time interaction (P<0.05); until autumn, the body weight of Mo-supplemented groups were higher than those of ram and wether lambs given Mo+S. Ovarian or testicular functions were delayed more severely for Mo- than Mo+S-supplemented groups. Mean concentrations of LH were affected by Mo*S*gonadal influence*time interaction (P<0.05); the mean LH values of Mo-supplemented ram and ewe lambs were higher than the Mo+S-supplemented group, whereas a reverse trend was observed for wether lambs. The amplitude of LH peaks was affected by Mo*S*gonadal influence*time interaction (P<0.05); for ram lambs, LH peak amplitude was higher for Mo than Mo+S-supplemented groups, whereas for wether and ewe lambs the reverse trend was noted. Mean concentrations of serum Cortisol and Cortisol peak amplitude were affected by Mo*S interaction (P<0.05); the mean Cortisol concentration and peak amplitude for the Mo-supplemented group were higher than those for the Mo+S-supplemented group. The frequency of LH and Cortisol peaks did not differ (P>0.10) among diet groups. In conclusion, Mo supplementation of cereal-based diets containing a high concentration of Cu did not adversely affect lamb growth. However, the effect of high dietary Mo on reproductive function appears to depend on the dietary level of S and the induction of high serum RCu (thiomolybdate). Further investigations on the effects of Mo and thiomolybdate on endocrine function may provide a nutritional basis for improving reproductive efficiency in ruminants.
Land and Food Systems, Faculty of
Graduate

Conjugated linoleic acid (CLA) is produced in the rumen by isomerization of linoleic acid and has been shown to be anticarcinogenic. The objective of this study was to determine the effects of feeding dietary CLA to pre-ruminant lambs or linoleic acid-rich safflower oil to weaned ruminating lambs. Fat content, CLA content and fatty acid (FA) composition of diaphragm, leg, rib, subcutaneous (SC) adipose and liver tissues were determined. The triacylglycerol (TAG) fractions of the total lipid (TL) from the diaphragm, rib and SC adipose tissues were analyzed for FA composition and FA positional distribution. The phospholipid (PL) fractions of the TL were analyzed for FA composition. The positional (PL) fractions of the TL were analyzed for FA composition. The positional distribution of FAs of liver PL was determined. Tissue fat content was affected by diet only in SC adipose tissue. Dietary supplementation with safflower oil increased the fat content of the subcutaneous adipose tissue whereas CLA supplementation resulted in decreased (P<0.05) fat content. Dietary supplementation with safflower oil increased (P<0.05) the CLA content of tissues by more than 200% whereas dietary supplementation with CLA did not affect CLA content. Positional distribution analysis indicated that CLA tends was localized to the sn-1/3 positions of TAG and the sn-2 position of the liver PL.
xiii, 74 leaves : ill. ; 28 cm.

Bibliography : leaves 120-133. Defines the sources of reproductive wastage in FecB FecÊ Booroola Merino x South Australian Merino ewes and examines factors associated with the survival of embryos, fetuses and lambs with the aim of improving net reproduction efficiency. Experiments were conducted to define the problem; to examine factors affecting embryonic and fetal loss; and, to investigate factors influencing wastage at lambing.

Thesis (MScAgric)--Stellenbosch University, 2011.
ENGLISH ABSTRACT: The following study is to determine if a creep feed balanced for limiting essential amino acids (EAA) at a certain non structural carbohydrate (NSC) level will elicit greater responses than lambs reared on a commercial creep feed. Lysine, Threonine, Methionine, Isoleucine, Phenylalanine and Leucine were determined as the limiting amino acids for nursing lambs. These amino acids were incorporated into the creep feed treatments CF1 and CF2 representing 157 g CP/kg, 477 g NSC/kg and 179 g CP/kg, 508 g NSC/kg, respectively. A commercial creep feed with no optimisation for EAA is represented as CFC with 139 g CP/kg and 455 g NSC/kg. A negative control (CON) treatment represents lambs receiving no creep feed but with ad libitum access to suckle their dams while feeding on kikuyu pasture. A growth trial was conducted on Merino x Döhne-Merino cross twin lambs averaging a birth weight of 4.42 kg ± 0.11 for 60 days following with a digestibility trial towards the end of the trial. Half of the lamb crop was slaughtered at an average live weight of 23.6 kg ± 0.56. The M. longissimus dorsi was removed on both the left and right half of the carcass between the 2nd - 3rd last thoracic vertebrae and the 4th - 5th lumbar vertebrae. A sample from the rumen wall was taken at the rumino-reticular fold to determine development characteristics. Results indicate that the feed conversion ratio for the CFC lambs were better than CF1 (P = 0.052) but not more than CF2 (P = 0.307). The FCR was 0.88, 1.19 and 1.01 (kilogram feed required to gain 1 kg in bodyweight) for CFC, CF1 and CF2, respectively. Dressing percentage was higher for CF2 than for both CFC (P = 0.012) and CF1 (P = 0.077). Along with BUN data it was concluded that the high CP level of CF2 resulted in the higher fat deposition. The optimised creep feeds had higher nitrogen and energy balances than the commercial CFC, this implicates that the optimised creep feeds were more efficiently utilised. Optimised creep feed treatments had longer papillae than CON (P < 0.0001). Papillae of creep feed 2 was longer than CFC (P = 0.0537). Papillae width decreased as the NSC level increased thus it is surmised that higher NSC levels resulted in longer but thinner papillae. Rumen muscularization was equally developed between all the treatments and was ascribed to the lambs’ access to course roughage. Meat quality in terms of physical and chemical characteristics was found to be in range with that expected for lambs at higher slaughter weights (40 kg). In conclusion, the balancing of the limiting EAA increases the benefits of creep feeding while simultaneously being more efficiently utilised. Intensive sheep production systems may benefit from the feeding of such creep feeds provided it fits economically into their farming system.
AFRIKAANSE OPSOMMING: Die volgende studie is om te bepaal of 'n kruipvoer wat gebalanseerd is vir beperkende essensiële aminosure (EAA) by 'n vasgestelde nie-strukturele koolhidraat (NSK) vlak verbeterde groei sal ontlok teenoor lammers wat grootgemaak word op 'n kommersiële kruipvoer. Lisien, Treonien, Metionien, Isoleusien, Fenylalanien en Leusien is bepaal as die beperkende aminosure vir suipende lammers. Hierdie aminosure is opgeneem in die geoptimiseerde kruipvoer behandelings CF1 en CF2 wat 157 g RP/kg, 477 g NSK/kg en 179 g RP/kg, 508 g NSK/kg onderskeidelik verteenwoordig. 'n Kommersiële kruipvoer met geen optimalisering vir EAA is verteenwoordig as CFC met 139 g RP/kg en 455 g NSK/kg. 'n Negatiewe kontrole (CON) behandeling is verteenwoordig deur lammers wat geen kruipvoer ontvang het nie, maar wat ad libitum toegang tot hul ooi gehad het om te soog terwyl die ooi op ‘n kikoejoeveld wei. 'n Groei proef is uitgevoer met Merino x Döhne-Merino kruis tweelinglammers met ‘n gemiddelde geboorte gewig van 4,42 ± 0,11 kg vir 60 dae en 'n verteerbaarheids proef is na aan die einde van die studie uitgevoer. Helfte van die lam kudde is geslag by die lewende gewig van 23,6 ± 0, 56 kg. Die M. longissimus dorsi was op beide die linker-en regter helfte van die karkas tussen die 2de - 3de laaste torakale werwels en die 4de - 5de lumbale werwels verwyder. 'n Monster van die rumen wand is geneem langs die rumino retikulêre vou sodat die rumen ontwikkeling eienskappe daarmee bepaal kon word. Resultate dui daarop aan dat die voeromsetverhouding (VOV) vir CFC lammers beter was as vir CF1 (P = 0,052), maar nie meer as vir CF2 (P = 0,307) nie. Die VOV was 0,88 , 1,19 en 1,01 (kilogram voer wat nodig is om 1 kg liggaamsmassa aan te sit) vir CFC, CF1 en CF2 onderskeidelik. Uitslag persentasie vir CF2 was hoër as beide CFC (P = 0,012) en CF1 (P = 0,077). Saam met die bloed, urea en stikstofbalans data is daar tot die gevolgtrekking gekom dat die hoë RP inhoud van CF2 gelei het tot ‘n hoër vetneerlegging. Die geoptimaliseerde kruipvoere het ‘n hoër stikstof- en energiebalans gehad teenoor die kommersiële CFC behandeling wat dus impliseer dat die optimale kruipvoere doeltreffender benut was. Die geoptimaliseerde kruipvoer behandelings het langer papillae gehad as CON (P < 0,0001). Papillae lengte van die CF2 behandeling is langer as die van CFC (P = 0,0537). Papillae breedte het dunner geraak soos wat die NSK-vlak gestyg het dus word vermoed dat hoër NSK-vlakke langer maar dunner papillae tot gevolg het. Rumen bespiering is ewe ontwikkeld tussen al die behandelings en word toegeskryf aan die lammers se toegang tot growwe ruvoer. Vleis kwaliteit in terme van fisiese- en chemiese eienskappe was inlyn met wat verwag kan word vir lammers by hoër slaggewigte (40 kg). Ten slotte, die balansering van beperkende aminosure verhoog die voordele van kruipvoeding en word terselfdertyd doeltreffender benut. Intensiewe skaap produksie stelsels kan dus voordeel trek uit die voeding van sodanige kruipvoere mits dit ekonomies pas in die boerdery stelsel.

Desert bighorn sheep (Ovis canadensis mexicana) are an endangered species in New Mexico. Many of the small, isolated populations of desert bighorn are declining, and factors affecting their growth rates include low lamb recruitment and high mortality of adults due to cougar predation. No one has previously reported cause-specific mortality rates for desert bighorn lambs. My objectives were to determine the causes, extent, and timing of lamb mortality in the Fra Cristobal Mountains, New Mexico, USA. I tested 3 capture techniques during 2001 and 2002: approaching lambs on foot and restraining them by hand; jumping from a helicopter and restraining them by hand; and firing a net-gun from a helicopter. I captured 6 lambs by hand on the ground, 4 lambs by hand from the helicopter, and 11 lambs from the helicopter with a shoulder-mounted and skid-mounted net-gun. No injuries occurred to lambs or capture personnel. The hand capture technique allowed me to capture very young lambs. I then monitored lambs for mortality, and examined carcass and site characteristics to determine cause. I found that the primary proximate cause of lamb mortality was cougar predation, followed by golden eagle predation. Coyotes and bobcats did not kill lambs. Although 1 lamb died from pneumonia, disease was not a critical factor affecting lamb recruitment. I measured habitat characteristics at sites where adults and lambs were killed by cougars and paired control sites, and derived habitat characteristics at predation sites, relocation sites representing used areas, and random sites representing available areas. Visibility was lower at predation than control sites, while slope, elevation, and ruggedness were lower at predation than relocation sites, and predation sites were closer to water and roads than random sites. I suggest selective cougar control of habitual sheep killers over the short term may be an appropriate management strategy to enhance the recovery of desert bighorn populations, while recognizing the importance of carnivore populations to ecosystem health. Wildlife managers may consider prescribed burning to reduce vegetation encroachment and increase visibility and forage quantity and quality. Additionally, assessment of desert bighorn and cougar use of artificial water developments would be beneficial.

Thesis (MScAgric)--University of Stellenbosch, 2002.
ENGLISH ABSTRACT: The Dorper is numerically the second most abundent of all the sheep breeds in South Africa. It is the most numerous sheep breed in the dry arid areas of South Africa which make out a very big portion of the natural grazing in South Africa. In this study the feedlot performance was specifically investigated since so little research has been done in this regard. In the first study (Chapter 1), the production efficiency, body components and commercial yield of 13 Dorper and 12 Merino lambs were investigated. A pelleted diet was fed ad lib and the water intake per day was measured. Lambs were slaughtered at 30kg and at 40kg live weight and cut up according to the South African commercial cuts. The weights of the organs, head, feet, skin and carcass were also recorded. Results from the first study showed that Dorpers had a lower (P<0.05) water efficiency (285.97 mVkgO75/day) than the Merinos (240.07 mVkg075/day), but had a higher (P<0.05) nitrogen retention. The head, feet, skin, heart, lungs, kidneys and diaphragm of Merino lambs were heavier (P<0.05). Merinos had heavier (P<0.05) breast and shank and thick rib (only at 40kg live weight) cuts. But the Dorper had a significantly heavier hindquarter (buttock and loin) which is the high-priced cut of any carcass. It seems that the Dorper will do well under feedlot conditions, and would possibly make a better commercial meat producer than the Merino under all circumstances. In the second study (Chapter 2), the free-ranging Dorper on natural grazing were compared with 7 Dorper lambs in the feedlot study. The essential amino acids in the duodenal contents were compared. The free-ranging Dorpers were randomly slaughtered at 40 kg live weight and a duodenal sample was collected. The feedlot Dorpers were also slaughtered at 40 kg live weight and a duodenal sample was taken. The second study indicated no significant differences between the EAA composition of the duodenal samples, whether protein quantity was taken into account (gAA/100g crude protein (CP)) or not (expressed as % of lysine). The chemical scores indicated that the two most limiting amino acids in the duodenal digesta for whole empty body growth were: arginine and histidine. Excess levels of amino acids tend to be present in all three duodenal digesta samples (isoleucine, leucine, lusine, methionine, phenylalaline, threonine and valine). The whole empty body EAA composition (g AA/100 g crude protein) was as follows 7.10 arginine; 2.40 histidine; 3.31 isoleucine; 7.22 leucine; 6.61 lysine; 1.62 methionine; 3.91 phenylalanine; 3.77 threonine and 4.85 valine. The composition can serve as an example of the ideal EAA requirements for whole empty body growth between 30 and 40 kg live weight of Dorper ram lambs. The duodenal amino acid concentrations of the free-ranging Dorper compared well with those of the feedlot Dorpers which suggests that the microbial organisms have a big influence on the amino acid concentration which reaches the intestines.
AFRIKAANSE OPSOMMING: Die voerkraal prestasie en essentiele aminosuur behoeftes van groeiende Dorper lammers: The Dorper is getalgewys die tweede mees talryke skaapras in Suid-Afrika. Dit is die mees talryke skaapras wat in die drce woestynagtige gebiede van Suid-Afrika aangetref word. Die gebiede beslaan die grootste oppervlakte van Suid-Afrika se natuurlike weiveld. In die studie is voerkraal prestasie van die Dorper nagevors, spesifiek omdat daar so min navorsing op hierdie gebied gedoen is. In die eerste studie (Hoofstuk 1) is die produksie doeltreffendheid, liggaams komponente en kornrnersiele produksie van 13 Dorper- en 12 Merino lammers ondersoek. 'n Verpilde rantsoen is ad lib gevoer en die water inname per dag is ook gekontroleer. Die lammers is geslag op 30 en 40 kg lewende gewig en die karkasse is daarna opgesny volgens die Suid-Afrikaanse kornmersiele karkassnitte. Die resultate van die eerste studie het getoon dat Dorpers 'n laer water potentiaal (P<0.05) (285 97 mflkgO 75/dag) as die Merinos (240.07 mVkg075/dag) het. Dorper lammers het ook 'n hoer (P<0.05) stikstof retensie. Die kop, vel, pote, hart, longe, niere en diafragma van Merino lammers was swaarder (P<0.05). Merinos se brisket en dikrib snitte weeg ook swaarder (P<0.05). Die Dorper het 'n beduidende swaarder agterkwart (len de en boud) gehad, wat die duurste snit is van enige karkas. Die Dorper het baie goed gedoen in die voerkraal toestande en sal waarskynlik onder aile omstandighede 'n hcer vleisproduksie op die Merino lewer. In die tweede studie (Hoofstuk 2), is die vryweiende Dopers op natuurlike weiding vergelyk met die Dorpers in 'n voerkraal. Die twee groepe Dorpers se essensiele aminosuur samestelling in hul dunderms is bepaal en vergelyk om te bepaal of daar enige tekorte teenwoordig is. Die Dorpers in die veld en in die voerkraal is op 40 kg lewende gewig geslag en monsters van die dunderm inhoud is gekollekteer. Die monsters is ontleed om te bepaal of daar enige betekenisvolle verskille in die essensiele aminosure van die dunderm inhoud tussen die veld Dorpers en voerkraal Dorpers was. Die tweede studie het geen betekenisvolle verskille getoon tussen die dunderm monsters se essensiele aminosure, of die hoeveelheid proteien (gAA/100g) in aanmerking geneem is of nie (uitgedruk as % lisien). Die chemiese telling dui aan dat die twee mees beperkende aminosure in die dunderm inhoud vir lee liggaam groei arginien en histidien was. Oormaat vlakke van aminosure kom voor in al drie dunderm inhoud monsters (isoleusien, leusien, lisien, metionien, femielalanien, treonien en valien). Die totale lee liggaam essensiele aminosuursamestelling (g aminosuur/100g ruprotein) was soos volg: 7.10 arginien; 2.40 histidien; 3.31 isoleusien; 7.22 leusien; 6.61 lisien; 1.62 metionien; 3.91 fenielalanien; 3.77 treonien en 4.85 valien. Hierdie aminosuursamestelling kan as 'n aanduiding dien vir die ideale aminosuurbehoeftes van Dorper ram lammers vir totale lee liggaamsgroei vanaf 30 tot 40 kg lewende massa. Die dunderm aminosuur konsentrasie van die Dorper in die veld stem goed ooreen met die van die voerkraal Dorper. Dit toon waarskynlik dat die mikrobe organismes in die rumen In groot invloed het op die aminosuur samestelling wat die dunderm bereik.

The abomasal helminth Teladorsagia circumcincta is one of the most economically important parasites to affect the farming of sheep and goats. T.circumcincta infection is particularly detrimental to lambs, in which it can cause pronounced morbidity and severe production losses. Due to the spreading resistance of this parasite to all currently available classes of anthelmintic drugs, it is having an increasingly severe impact on the sheep industry with significant implications for sheep welfare. Infection of sheep with T.circumcincta triggers local changes in the abomasum characteristic of a T helper type-2 (Th2) driven immune response, including local eosinophilia, mastocytosis and increased mucus production, which leads to expulsion of the parasite. However, this protective immunity develops slowly during repeated exposure, wanes rapidly, and does not appear to be evident in young lambs. Vaccination to provoke early onset of protective immunity has therefore been suggested as an alternative means of control in the face of spreading anthelmintic resistance. Greater understanding of the development of immunity to T.circumcincta, and why this is delayed in lambs, would be useful in vaccine development. This thesis focuses on cytokine transcription profiling of the ovine abomasal mucosa and local lymphatic tissues. Changes in cytokine transcription over the course of a challenge infection with T.circumcincta were defined in helminth naïve sheep, and in previously infected sheep which have developed a degree of immunity during an eight week trickle infection, to clarify the mechanisms by which this immunity is orchestrated. This work demonstrated a clear Th2 cytokine response in the abomasal mucosa over the course of infection, which developed earlier and was more pronounced in the previously infected sheep; possibly owing to a population of polarised Th2-type cells built up during the previous infection. Suppression of Th1 cytokine transcription was also a prominent finding in the draining lymph node, which likewise occurred earlier in the previously infected sheep. Repetition of this experiment using younger lambs provided a possible explanation for the reduced resistance to T.circumcincta in this age group. While Th2 and proinflammatory cytokine responses in the abomasal mucosa demonstrated similar trends to those found in the older sheep, little suppression of Th1 cytokine transcription was observed in the draining lymph node. It is therefore suggested that the increased susceptibility of young lambs to T.circumcincta is not due to an inability to generate adequate Th2 responses, but an inability to suppress transcription of antagonistic Th1 cytokines.

Lamb survival and productivity from birth to weaning and lamb postweaning management harvest are areas that the US sheep industry needs to become more efficient at to remain profitable. Western white-faced ewes were supplemented HIGH (12.5% rumen by-pass protein, 880 IU/kg of supplemental Vitamin E, 176 ppm chelated Zn, and 72.7 mg/kg chlortetracycline) or LOW (7.56% rumen by-pass protein, with no supplemental Vitamin E, chelated Zn, or chlortetracycline) supplements at 0.227 kg•ewe -1•d -1 during late gestation. Ewes of different age and body condition scores were individually supplemented for 29 d prior to expected lambing. Thereafter, each ewe was mass fed the appropriate supplement until lambing. In Experiment 3, approximately 600 ewes were group fed HIGH or LOW supplements over 2 yr. Differences in antibody transfer from ewe to lamb were detected in supplemented ewes of different age (P < 0.10); however, lamb production was not different (P > 0.10) for all 3 experiments. To investigate lamb post-weaning management, terminally sired lambs (n = 72) were randomly assigned to 1 of 4 backgrounding treatments. Lamb backgrounding treatments were: ad libitum access to 80% alfalfa: 20% barley pellets (PELLET); cool season grass paddock grazing (GRASS); remain with ewe flock on fall dormant range (LATE WEAN); wean for 96 h and returned to ewe flock on dormant range (RANGE). Background treatments were applied for 29 d. Thereafter, lambs were finished on a corn based diet. Lamb BW and ultrasound measurements were taken at weaning, after background treatment, after feedlot step-up and at the conclusion of the finishing period. Pen intake was measured. Lambs backgrounded on PELLET were heavier (P < 0.10) than all other treatments after the backgrounding period and at the end of the feedlot period. Lambs backgrounded on PELLET had the greatest intakes and ADG (P < 0.10) during the feedlot period. At beginning and end of the feedlot period, PELLET and GRASS lambs had larger (P < 0.05) LM areas than RANGE and LATE WEAN treated lambs. Under the condition of the studies, late gestational supplements did not improve ewe productivity and backgrounding treatments on dormant range diminished feedlot productivity.

The aim of this study was to evaluate the Small Ruminant Nutrition System (SRNS) model’s performance predictions for lambs under South African conditions using growth and body composition data of early- (Dorper) and late-maturing (South African Mutton Merino), indigenous sheep breeds. The Cornell Net Carbohydrate and Protein System (CNCPS) biological model has consistently been modified to include recent information. This has led to the development of the SRNS model, but up to now the SRNS model has only been validated with European sheep breeds under European conditions. Thirty two Dorper, 16 male and 16 female lambs, and 36 South African Mutton Merino, 18 male and 18 female lambs, were fed a grower diet for the experimental period of 60 days. Three groups of lambs of each breed were slaughtered as the lambs reached pre-determined target weights. The first group of 24 animals (slaughter group 1) was slaughtered at the onset of the experiment at a live weight of 20 kg. With the second group (slaughter group 2) the South African Mutton Merinos were slaughtered at an average weight of 35 kg and the Dorpers at an average weight of 30 kg. The last group (slaughter group 3) had an average weight of 50 kg for the South African Mutton Merinos and 40 kg for the Dorpers at slaughter. Using the data from this trial, predictions of the average daily gain (ADG), feed intake (DMI), empty body gain and the composition of the empty body gain were used to evaluate the model. The animals were divided into three slaughter groups, based on growth stage, for the determination of body composition data. Energy value of gain (EVG), fat and protein content on a shrunk and empty body weight basis were compared with the corresponding values predicted by the SRNS. Growth composition of the lambs was determined by dividing them into two growth periods. Average daily gain and DMI were evaluated in the experiment, and results compared to the mean ADG and DMI predictions obtained from the SNRS model. Two different equations were compared to estimate EVG and two sets of coefficients were also compared for the EVG. Five different equations were compared to estimate the efficiency of conversion of metabolisable energy (ME) to net energy (NE) for gain, kg. The correction factor to adjust for the increase in the size of the visceral organs as nutrient intake increases and the coefficient for the effect of gender on maintenance requirements were tested for relevance of use in the SRNS. Overall, based on these evaluations it appears that the original SRNS model gave the best predictions when compared to any of the modifications tested. With regards to ADG the model over-predicts the requirements of the lambs in the early growth stage and under-predicts the requirements of the lambs in the later growth stage. The DMI predictions that were made using the original SRNS were accurate. The evaluation of the SNRS predictions in relation to the composition of gain indicated that this model over-predicted both the fat and the protein content of gain. The predictions were accurate, however the precision was low. The low precision was probably due to the lack of variation in the measured range of fat and protein content of gain. Before field application further studies and adjustments to the SRNS model is required, especially with regard to predictions on the fat and protein content of gain and over or under predictions of ADG during different growth stages of Dorper and South African Mutton Merino lambs.
Dissertation (MSc)--University of Pretoria, 2013.
gm2014
Animal and Wildlife Sciences
unrestricted

Invitro synthesis and degradation capabilities and the cathepsin D activity of the skeletal muscles of experimentally induced Selenium-Vitamin E deficient lambs were investigated. Twenty-one Dorset x Coopworth x Suffolk lambs were blocked by weight and assigned to one of the following treatments: 1) a basal diet of 85% whole shelled corn and 15% mixed grass hay plus a mineral supplement that was low in Se and E (-Se-E), 2) the basal diet and deficient mineral mixture as fed in treatment 1 with the addition of a casein encapsulated fat supplement (-Se-E+fat), 3) the basal diet plus a mineral mixture which contained supplemental Se and E (+Se+E). Upon completion of the feeding trial, lambs which had been receiving the -Se-E treatment had the greatest body and individual muscle weights. The -Se-E+fat treatment had the lowest degradation rates and the highest synthesis rates. Cathepsin D activity was found to be lowest in the -Se-E+fat treatment. The -Se-E treatment was observed to have the highest degradation rate and the next highest synthesis rate indicating an increased rate of muscle turn-over. In all cases, the degradation rates were positively correlated with cathepsin D activity.
Master of Science

The effect of post-weaning supplementation of April-born Polypay and White Dorper lambs grazing alfalfa/orchardgrass pasture during two grazing seasons from June to September was studied. One hundred seventy Polypay and 133 White Dorper lambs were randomly allotted to supplemented (2% BW daily) and unsupplemented groups. It was discovered that Polypay lambs weighed more than White Dorpers at wearning, when the grazing season began, and at the end of the 80 (Year 1) and 85 (Year 2) grazing season (P < 0.01). Polypay lambs gained faster (P < 0.01) than White Dorpers. Supplemented lambs gained faster (P < 0.01) than unsupplemented and Polypays had a greater response to supplementation (P < 0.01) than White Dorpers. Polypays had higher (P < 0.01) fecal egg counts, an indicator of Haemonchus contortus infestation. Supplementation did not have any consistent effect on reducing Haemonchus contortus infestation. Differences in forage characteristics of Polypay and White Dorper lambs did appear. Differences in alfalfa and orchardgrass dry matter, neutral detergent fiber, acid detergent fiber, and crude protein availability were measured by subtracting enter from exit availabilities. The largest decrease of alfalfa components from exit to enter was found with unsupplemented Polypays. No consistent effect was found for orchardgrass components.

FundaÃÃo de Amparo à Pesquisa do Estado do CearÃ
The objective of the present study was to evaluate the effect of food restriction and sexual group on intake, digestibility of nutrients: dry matter (DM), organic matter (OM), mineral matter (MM), crude protein (CP), ether extract (EE), neutral detergent fiber (NDF), acid detergent fiber (ADF), non-fibrous carbohydrates (NFC), total carbohydrates (TC), total digestible nutrients (TDN) and diel behavior patterns intake of Santa Ines lambs. A total of 30 sheep was used, with average initial weight of 13.00 Â 1.49 kg in a completely randomized design in factorial 3x2, with three levels of restriction (ad libitum, 30 and 60%) and two sexual groups (castrated and uncastrated). The animals were fed on experimental diet composed of a forage:concentrate ratio of 60:40, with Tifton-85 hay (Cynodon spp.) as roughage. There was no sexual group effect or interaction between sexual group and food restriction levels for all variables analysed (P>0.05). The consumption of all nutrients were influenced by food restriction levels (P<0.05), decreasing according to the increase in restriction levels. Conversely, nutrient digestibility coefficients increased proportionally with food restriction levels (P<0.05). The feeding behavior variables were influenced by food restriction (P<0.05). Variations in feed time (hour/day), rumination efficiency (g DM/hour) and (g NDF/hour), ruminating time (hour/day) and total chewing time (hour/day) decreased with rising levels of food restriction (P<0.05). For the âFeed efficiency‟ variable (g DM/hour) and (g NDF/hour), food restriction led to an increase in efficiency of the restricted animals (P<0.05). Similarly, the increase in levels of food restriction promoted greater time spent in idleness restriction of animals (P<0.05). The variable number of ruminal bolus (No./day) and ruminating chewing number reduced with food restriction (P<0.05). However, chewing ruminating time increased with the restriction (P<0.05). As conclusion, food restriction promotes a reduction in nutrient intake and increased digestibility of the diet, thus providing increased efficiency in the absorption of nutrients in animals undergoing the level of 60% food restriction. The feeding behavior patterns are also altered by dietary restriction, especially the food expenditures times, ruminating and idleness and ruminating chewing patterns.
Objetivou-se com o presente estudo avaliar o efeito da restriÃÃo alimentar e da classe sexual sobre o consumo, digestibilidade dos nutrientes: matÃria seca (MS), matÃria orgÃnica (MO), matÃria mineral (MM), proteÃna bruta (PB), extrato etÃreo (EE), fibra em detergente neutro (FDN), fibra em detergente Ãcido (FDA), carboidratos totais (CHOT), carboidratos nÃo fibrosos (CNF), nutrientes digestÃveis totais (NDT) e os padrÃes nictemerais do comportamento ingestivo de cordeiros Santa InÃs. Foram utilizados 30 ovinos com peso mÃdio inicial de 13,00 Â 1,49 kg, em delineamento inteiramente casualizado em esquema fatorial 3x2, com trÃs nÃveis de restriÃÃo (ad libitum, 30 e 60%) e duas classes sexuais (castrados e nÃo castrados). Os animais foram alimentados com dieta experimental em relaÃÃo volumoso:concentrado de 60:40, sendo o feno de capim-Tifton 85 (Cynodon spp.) utilizado como volumoso. NÃo houve efeito de classe sexual ou interaÃÃo entre classe sexual e nÃvel de restriÃÃo alimentar para todas as variÃveis analisadas (P>0,05). O consumo de todos os nutrientes foi influenciado pelos nÃveis de restriÃÃo alimentar (P<0,05), decrescendo de acordo com o aumento nos nÃveis de restriÃÃo. Inversamente, os coeficientes de digestibilidade dos nutrientes aumentaram proporcionalmente aos nÃveis de restriÃÃo alimentar (P<0,05). As variÃveis de comportamento ingestivo foram influenciadas pela restriÃÃo alimentar (P<0,05). As variÃveis tempo de alimentaÃÃo (h/dia), eficiÃncia de ruminaÃÃo (g MS/h) e (g FDN/h), tempo de ruminaÃÃo (h/dia) e tempo de mastigaÃÃo total (h/dia) decresceram com o aumento nos nÃveis de restriÃÃo alimentar (P<0,05). JÃ para a eficiÃncia de alimentaÃÃo (g MS/h) e (g FDN/h), a restriÃÃo alimentar ocasionou um aumento desta variÃvel dos animais em restriÃÃo (P<0,05). De forma semelhante, o aumento nos nÃveis de restriÃÃo alimentar, promoveu uma maior permanÃncia em Ãcio dos animais em restriÃÃo (P<0,05). As variÃveis nÃmero de bolos ruminais (nÂ/dia) e nÃmeros de mastigaÃÃo merÃcicas reduziram com a restriÃÃo alimentar (P<0,05). No entanto, o tempo de mastigaÃÃo merÃcica aumentou com a restriÃÃo (P<0,05). Conclui-se que a restriÃÃo alimentar promove a reduÃÃo no consumo de nutrientes e o aumento na digestibilidade da dieta, proporcionando assim, uma maior eficiÃncia na absorÃÃo dos nutrientes nos animais submetidos ao nÃvel de 60% de restriÃÃo alimentar. Os padrÃes de comportamento ingestivo tambÃm sÃo alterados pela restriÃÃo alimentar, principalmente os tempos gastos com alimentaÃÃo, ruminaÃÃo e Ãcio e os padrÃes de mastigaÃÃo merÃcicas.

Vitamin B₁₂ deficiency has been difficult to diagnose, mainly due to the vitamin's lack of biological significance in serum in which it is usually assayed. This research has investigated the marker of vitamin B₁₂/cobalt (Co) deficiency in sheep, methylmalonic acid (MMA), in comparison with serum and liver vitamin B₁₂ concentrations in farm situations where vitamin B₁₂ deficiency is expected in order to establish more accurate reference ranges for serum and liver vitamin B₁₂, and MMA. In addition, an attempt was made to ascertain the vitamin B₁₂ requirements of preruminant (PR) lambs, and to determine whether metabolic demand for vitamin B₁₂ influences tissue concentrations. Furthermore, since the vitamin is active in biological tissues in form of its coenzymes, 5’ -deoxyadenosylcobalamin and methylcobalamin, a preliminary assessment of variation in the distribution of these coenzymes in liver in different situations has been sought. The first trial was set up to find out if the addition of propionate to the PR lamb's diet stimulated the uptake and/or storage of vitamin B₁₂ in the liver as a reflection of the need to deal with the incoming propionate. Sixteen ten day old lambs (Dorset Down/Coopworth cross-bred) were housed indoors soon after birth and fed on milk replacer. For half of the lambs 7.5 % (w:w) of the milk powder was replaced by propionate. Within each group, four lambs were treated with 250 µg vitamin B₁₂ twice weekly. Supplementation with vitamin B₁₂ increased liver concentrations from ~250 to ~900 nmol/kg fresh tissue, but there was no effect of propionate. Propionate addition did, however, result in increased plasma vitamin B₁₂ concentrations in vitamin B₁₂ supplemented groups, values being 3323 and 2355 pmol/l in propionate supplemented and control groups, respectively. This suggested that diet could influence plasma vitamin B₁₂ concentrations. An attempt was made to quantify the PR lamb's ability to absorb vitamin B₁₂ from the alimentary tract by comparing the ability of intra-muscular (IM) and oral vitamin B₁₂ to raise plasma and liver vitamin B₁₂ concentrations. Twenty-seven three to four day old lambs from a farm with marginal Co status were housed indoors and fed on milk replacer. They were divided into three groups: control (n=3), IM treatment (n=12) and oral treatment (n=12). The two treatment groups were further subdivided into five sub-groups. These received, respectively, 0.2 (n=3), 0.4 (n=2), 0.8 (n=2), 1.6 (n=2) and 3.2 µg OH-cbl/d (n=3). The oral groups received tenfold the amount of the comparable IM groups, on the assumption that if oral absorption of the vitamin is about 10 % both groups would show similar increases in plasma and liver vitamin B₁₂ concentration. None of the IM groups showed any significant change in plasma or liver vitamin B₁₂. In the oral groups only the group on the highest dose of vitamin B₁₂, viz 32 µg/d, showed increases in plasma and liver concentrations. It was concluded that either absorption of vitamin B₁₂ was greater than 10 % or that the vitamin was retained better when administered orally. The amount retained in the livers of the lambs in the highest oral group was calculated to represent ~ 7.5 % of the dose. In a follow-up 24 h trial, 14 of the above lambs were divided into three groups: Control (n=3), oral (n=6) and IM (n=5) treatment. The IM group received 3.2 µg OH-cbl and the oral group tenfold the amount as single doses at 0800 h. Blood samples were taken at regular intervals throughout the 24 h period and assayed for vitamin B₁₂, Vitamin B₁₂ concentrations in the IM group rose steeply within the first hour after injection to a concentration that was calculated to reflect 100 % uptake of the vitamin. It rose more slowly over about 8 h in the oral group. From the area under the curve absorption of the oral dose was estimated to be ~ 7 %. The next experiment involved a farm where Co deficiency had been reported previously. In the first year, 50 pregnant two-tooth Half-bred ewes were divided randomly into two groups of 25. One group received a Co bullet plus 1000 µg OH-cb1 IM, the other group remained unsupplemented. In the following year the trial was repeated. Ewes from the previous year's trial (by then four-tooths) were augmented by a new cohort of pregnant two-tooths to make up numbers to 75. After lambing the lambs were divided into four groups: first by their dams' vitamin B₁₂ treatment, then half of each group received injections of vitamin B₁₂ at approximately three weekly intervals while the other half remained untreated. The trials lasted about five months, from mid-pregnancy until weaning. Pasture Co was at its lowest at lambing in both years, 0.09 and 0.10µg/g DM, respectively. In the first year, vitamin B₁₂ concentrations in the untreated ewes rose from 340 to 950 pmol/l in plasma and decreased in liver from 330 to 170 nmol/kg fresh tissue. In the Co treated group, vitamin B₁₂ concentrations in plasma rose from 500 to 1550 pmol/l and in liver from 310 to 560 nmol/kg fresh tissue. In the second year, vitamin B₁₂ concentrations in serum in the unsupplemented groups fell from 500 to 260 pmol/l around lambing before rising again to starting values at weaning, and liver vitamin B₁₂ concentrations fell from 450 at the start to 230 nmol/kg fresh tissue at the end of the trial. Serum vitamin B₁₂ concentrations in the two-tooth supplemented group rose from < 500 to > 3000 pmol/l whereas in the four-tooth supplemented group serum vitamin B₁₂ levels started at ~2800 and rose to nearly 5000 pmol/l. The supplemented four-tooths maintained higher liver vitamin B₁₂ concentrations throughout compared to the supplemented two-tooths, viz 680 compared to below 400 at the start and 900 versus 650 nmol/kg fresh tissue at weaning, respectively. MMA in the untreated groups rose to 15 and to 8 µmol/l during early lactation in the first and second years, respectively, whereas MMA in the treated groups stayed below 3 µmol/l in the first season and below 1.5 µmol/l in the second season. There was a live weight response to treatment in the ewes as the unsupplemented groups showed a significantly lower weight gain during the trials than the supplemented groups, viz 10.0 versus 13.6 kg in the first year, and 10.6 versus 13.3 kg in the four-tooths and 9.9 versus 12.1 kg in the two-tooths in the second year. There was also a significant difference in faecal egg count (FEC) in the first year. FEC in the untreated group was higher during lactation than in the treated group, viz 590 versus 170 eggs per gram wet faeces (epg), respectively. In the second year, the two-tooths had a higher FEC than the four-tooths, viz 120 versus 40 epg during the same time span, respectively. While there was a trend for treatment having an effect on FEC similar to that in the first year it was not significant. Supplementation of ewes in the first year increased mean milk vitamin B₁₂ concentrations at lambing from 800 to 1400 pmol/l and at weaning from 1750 to 4000 pmol/l. In the second year, Co bullet treatment increased milk vitamin B₁₂ concentrations in the four-tooths and two-tooths from 1500 and 2300 to 4000 and 2900 pmol/l at lambing, and from 1800 and 1400 to 6200 and 4500 pmol/l at weaning, respectively. Treatment of ewes increased vitamin B₁₂ concentrations in the lambs which were not themselves supplemented. Plasma values in the first year increased from 160 to 325 pmol/l soon after birth and from 650 to 900 pmol/l at weaning, and liver values from 75 to 140 nmol/kg fresh tissue soon after birth and from 150 to 240 nmol/kg fresh tissue at weaning. In the second year, plasma vitamin B₁₂ concentrations increased from 160 to 380 pmol/l soon after birth and from 500 to 700 pmol/l at weaning, and in liver from 130 to 260 nmol/kg fresh tissue soon after birth and from 220 to 340 nmol/kg fresh tissue at weaning. There was also a significant effect of ewe supplementation on lamb MMA in 1997/1998 when values decreased from 19 to 8 µmol/l around the time of rumen development. MMA in the second year stayed below 3 µmol/l throughout in all groups of lambs. There was no difference in LWG between any groups of lambs. FEC was lowest in the group where both ewes and lambs were supplemented and highest in the group where neither ewes nor lambs were treated. Further investigations were conducted on farms in Southland with lambs post-weaning in order to compare changes in serum and liver vitamin B₁₂ with serum MMA and LWG to determine the critical time and level of deficiency. In the first year, three farms with 50 lambs each participated. Lambs from each farm were allocated to five groups of 10 animals each. The first group received a Co bullet at weaning, and each month another group was treated with a Co bullet. The lambs were weighed monthly, and blood and liver samples were taken prior to treatment and each subsequent month from five lambs of the first supplemented group. The trial lasted about four months. Serum vitamin B₁₂ concentrations in lambs at weaning were between 500 and 1000 pmol/l. Although supplementation increased serum levels for the first month this was followed by a drop to near or below starting concentrations. An exception was Farm 3 where serum vitamin B₁₂ concentrations rose again at the end of the trial. Liver vitamin B₁₂ concentrations also showed an overall decline from starting levels (200 to 300 nmol/kg fresh tissue) to the end of the trial (100 to 200 nmol/kg fresh tissue). MMA started around 2 µmol/l and reached between 6 and 7 µmol/l in the untreated lambs on Farms 1 and 3 two months after weaning before decreasing to around 3 µmol/l at the end of the trial, whereas the treated lambs maintained MMA concentrations around 2 µmol/l. On Farm 2 MMA started just below 5 µmol/l, decreased to around 1 µmol/l for treated and untreated lambs one month later and rose again to between 2.5 and 4 µmol/l, respectively, at the end of the trial. LWG was below average for all lambs (between 0.20 and 0.04 kg/d except for Farm I in the first month after weaning) but no significant differences were noted between treated and untreated lambs on any of the farms. Another trial was conducted on one of these farms in the following year. One hundred lambs were divided into two groups of 50 each at weaning and sampled monthly for about six months. One group was treated with two Co bullets, the other group remained untreated. Pasture Co was between 0.04 and 0.07 µg/g DM, yet serum levels for the untreated group stayed ~500 pmol/l throughout the trial. Serum vitamin B₁₂ concentrations for the treated group started at ~500 pmol/l, rose to ~2500 pmol/l before falling back to ~2000 pmol/l. Liver vitamin B₁₂ concentrations for the untreated and treated groups were 529 and 427 nmol/kg fresh tissue at weaning, respectively. This decreased for both groups to ~350 nmol/kg fresh tissue one month after weaning. In the untreated lambs liver values decreased further to ~290 nmol/kg fresh tissue whereas they increased to ~450 nmol/kg fresh tissue for the treated group at the end of the trial. MMA concentrations started between 2 and 3 µmol/l for both groups and increased to 4.5 µmol/l for the untreated group one month later before falling back to 3.2 µmol/l. In the treated group MMA decreased to ~1µmol/l and stayed at that level throughout the trial. There was no difference in weight gain. In order to obtain an understanding of the distribution of corrinoids in biological tissues a High Performance Liquid Chromatography method was developed. The sensitivity of the analytical method meant that it was only practical to assay mainly liver samples because of the higher vitamin B₁₂ concentrations than in other tissues. The general finding was that the coenzyme 5’ –deoxyadenosylcobalamin (ado-cbl) constituted the highest proportion of corrinoids in liver (45 %), followed by analogues (28 %), OH-cbl (24 %) and lastly methy1cobalamin (3 %). Ado-cbl did tend to be proportionately higher in supplemented than in unsupplemented animals (56 and 42 %, respectively), whereas biologically non-active analogues tended to be higher in untreated than in treated sheep (29 and 21 %, respectively). It was concluded that in the farm trials Co deficiency was only mild or not present although deficiency would have been predicted from the low vitamin B₁₂ concentrations in serum and liver and from raised MMA values. Therefore, currently used thresholds in New Zealand appear to be too high for vitamin B₁₂, and overseas values for MMA do not seem to be appropriate. Revised marginal ranges of 100 to 200 pmol/l for serum, 100 to 200 nmol/kg fresh tissue for liver and 10 to 20 µmol/l for MMA are suggested. Further, this work shows that Co bullets were effective in elevating blood and liver vitamin B₁₂concentrations for longer than one year. In the trials with preruminant lambs it was found that maintenance requirements were met by the vitamin B₁₂ content of milk replacer. There is evidence from indoor and farm trials that vitamin B₁₂ from milk was much more readily absorbed than vitamin B₁₂ from supplements. It was estimated that suckling lambs probably require between 1200 and 4000 pmol vitamin B₁₂/d, depending on age.

Two experiments were conducted with sheep to determine the nutritional value of 'Lathco' flatpea (Lathyrus sylvestris) hay. In experiment 1, a finishing trial was conducted with 50 group fed crossbred lambs (25 ewes and 25 wethers) fed diets consisting of 70% chopped forage and 30% ground corn grain for 70 d. Five pens of five wethers and five pens of five ewes were selffed diets in which the forage consisted of 100:0, 75:25, 50:50, 25:75, and 0:100 proportions of alfalfa (Medicago sativa L.) and flatpea hay. Feed efficiencies decreased linearly (P<.05) as flatpea increased in the diet. Linear decreases (P<.05) were obtained in kidney and pelvic fat, backfat, leg conformation, and yield grade with increased flatpea in the diet. Blood urea-N (BUN), ruminal pH and NH3-N increased (P<.005) as proportion of flatpea increased. Total volatile fatty acid (VFA) and acetate concentration decreased linearly (P<.005) and propionate, isovalerate, and valerate levels increased linearly (P<.01) with increased proportions of flatpea hay. In experiment 2, 30 wether lambs were fed diets consisting of 100:0, 75:25, 50:50, 25:75 and 0:100 proportions of chopped alfalfa and flatpea hays in a digestion trial. Neutral detergent fiber (NOE), acid detergent fiber (ADE), cellulose, hemicellulose and energy digestibilities decreased linearly (P<.Ol) with increased levels of flatpea hay. Nitrogen retention was not different between sheep fed the different diets. Apparent absorbtion and retention of Ca decreased linearly (P<.05) with increased level of flatpea hay Ruminal pH and NHa-N, and BUN increased linearly (P<.OOl) as flatpea was increased in the diet. Ruminal total VEA, acetate and acetate to propionate ratio decreased linearly (P<.001) and propionate, isobutyrate, isovalerate, and valerate levels increased linearly (P<.001) as level of flatpea increased.

Master of Science

Objetivou-se avaliar diferentes maneiras de manejar o campo nativo durante o período hibernal para alimentar ovelhas no inicio de gestação e determinar a melhor metodologia para tal fim, por meio das características produtivas e comportamentais dos animais assim como modificação na estrutura e qualidade da pastagem. Para tal, foram testados, com delineamento em blocos casualizados com quatro tratamentos e três repetições, dois métodos de pastoreio (contínuo (LC) e rotativo (LR)) e dois níveis de oferta de forragem (12 e 18% OF). As variáveis utilizadas para descrever as características produtivas dos animais foram: ganho médio diário das ovelhas e cordeiros, escore de condição corporal das ovelhas e o ganho de peso, em unidade de área, das ovelhas, cordeiros e o ganho total por área. Além destes, foram avaliados parâmetros de comportamento ingestivo, que são o tempo diurno de pastejo, ruminação e outras atividades, número, tamanho e intervalo de refeições, número, tempo e número de passos entre estações alimentares e taxa de bocados. As variáveis medidas no pasto foram: massa de forragem, taxa de acumulo, altura, massa de folhas verdes, colmos, leguminosas e “outras espécies”, e as características bromatológicas (proteína bruta, FDN, etc.) do pasto ao longo do tempo de duração do experimento. Os resultados apontaram que as OF, apesar de provocar modificações significativas na massa de forragem e altura do pasto, teve pouca influencia nos parâmetros de comportamento animal em pastejo e pouca influencia no desempenho produtivo dos animais, provavelmente devido ao baixo contraste que as ofertas de forragem intermediárias proporcionaram durante o inverno. Os métodos de utilização da pastagem também não apresentaram influência marcante sobre o desempenho produtivo das ovelhas, mas modificou drasticamente o comportamento ingestivo dos animais. Os animais manejados em LR apresentaram menores tempos de pastejo do que os animais mantidos em LC, e esse tempo variou também entre os dias de avaliação. A interação dos dois fatores não teve influência no peso dos cordeiros ao nascer, porém, influenciaram as características estruturais e bromatológicas do pasto. Onde no manejo no inverno foi constituído pelo método contínuo e 12% de OF, a pastagem apresentou uma menor quantidade de outras espécies e presença predominante de espécies de melhor qualidade, ficando mais “limpa” e melhor qualidade nutricional na primavera. Essa melhor qualidade nutricional, por sua vez, apesar de não modificar significativamente os ganhos individuais de ovelhas e cordeiros, modificou a quantidade de peso vivo produzido em unidade de área.
The main objective was to evaluate strategies to manage the grassland during the winter season to feed ewes at the early pregnancy and determine the best method for this purpose, through the animal production characteristics, their ingestive behavior as well as modification of the structure and quality of the pasture. The experiment was set up in a randomized block design with four treatments and three replicates, two grazing methods (continuous (CS) and rotational (RS)) and two levels of herbage allowance (HA; 12 - and 18% LW). The variables used to describe the animals performance were: average daily gain of sheep and lambs, ewes body condition score and weight gain in unit area of the sheep, lambs and total gain per area. It was also assessed parameters of ingestive behavior as the diurnal grazing time, ruminating and other activities, number , size and range of meals, number, time and step number between feeding stations and biting rate. The variables measured in the pasture was: herbage mass, accumulation rate, height, mass of green leaves, stems, legumes and 'other species' and nutritive characteristics values (crude protein, NDF, etc.) of the pasture over all time of duration of the experiment. The results showed that the HA, although cause some significant changes in herbage mass and sward height, had little influence on animal behavior parameters and little influence on the productive performance of animals, probably due to the low contrast that intermediate herbage allowance provided. The grazing methods also had no significant influence on the performance of the sheep, but dramatically changed the ewes grazing behavior. The smaller area in the RS promoted a shorter grazing time than the time observed on a CS, and the grazing time on RS also varied during the days. The interaction of the two factors did not influence the weight of lambs at birth, however, influence the structural and chemical characteristics of the pasture. Where the management in winter was constituted by CS and 12% HA, the pasture had a lower amount of other species, being “cleaner” and, also presents a better nutritional quality in the subsequent spring. This improved nutritional quality, in turn, while not significantly modify the ewes and lambs individual gains, changed the amount of weight produced on unit of area, been more productive than other combinations.

Thesis (MSc Food Sc (Food Science))--University of Stellenbosch, 2010.
ENGLISH ABSTRACT: The aim of this study was to investigate the impact of an extensive (free-range) and intensive (feedlot) production system on the consumer’s intrinsic preference cues (physical attributes, chemical composition, fatty acid profile, aroma, flavour, initial juiciness, sustained juiciness, first bite, residue, instrumental tenderness) for three muscles (Biceps femoris, Longissimus dorsi, Semimembranosus) of Dohne Merino lambs (8 months). Secondly to investigate the effect of natural exercise (grazing, extensive production systems) or restrictive movement (intensive production systems), on the muscle fiber type composition of the same lamb muscles and the subsequent effect on the meat quality characteristics. Intensively raised lambs produced carcasses with a significantly higher dressing percentage, thicker subcutaneous fat layer (13th rib and 3rd/4th lumbar vertebra) and a greater fat ratio (carcass composition). Meat of intensively raised lambs had a higher (p < 0.050) Homo-glinolenic (C20:3n6), Eicosapentaenoic (C20:5n3), Docosapentaenoic acid (C22:5n3) content and n3:n6 ratio. Extensively reared lambs had a higher (p < 0.050) slaughter weight, cold carcass weight and the meat of these lambs had a higher myoglobin content. Results of this study indicate that intensively reared lambs produced meat with more favourable sensory characteristics compared to the extensive production system as well as a significant increase in sensory tenderness for Biceps femoris muscle. Overall the Biceps femoris muscle was the muscle that was primarily affected by the treatment (production systems). The Biceps femoris from intensively raised lambs contained significantly more intramuscular fat and type IIB muscle fibers whereas the Bicpes femoris of the lambs from the extensive production system contained more (p < 0.050) insoluble collagen and type I muscle fibers. During texture profile analysis (instrumental tenderness test) the Longissimus dorsi and Semimembranosus of extensively raised lambs required a higher (p < 0.050) compression force during the first cycle of compression, indicating that these muscles are tougher. The results of this study provided valuable insight into the impact of production systems on lamb meat quality and that the application of intensive production systems will increase the sensory characteristics of the selected muscles from Dohne Merino lambs, especially the tenderness of the Biceps femoris, which has a high retail value. On the other hand health conscious consumers will prefer extensively produced meat due to the favourable n3:n6 ratio, intramuscular fat content and the presences of less visible fat (subcutaneous).
AFRIKAANSE OPSOMMING: Hierdie studie was tweedoelig en is uitgevoer op die Biceps femoris, Longissimus dorsi en Semimembranosus spiere van Dohne Merino lammers (8 maande oud). Die eerste doel van die studie was om te bepaal wat die effek van ‘n ekstensiewe (weiding) en intensiewe produksie sisteem sal wees op vleis verbruikers se algemene kwaliteit voorkeure (fisiese eienskappe, chemiese samestelling, vetsuur profile, aroma, smaak, sappigheid, taaiheid,). Tweedens om te bepaal tot watse mate natuurlike oefening, verkry deur weiding asook beperkte beweging as gevolg van voerkraal omstandighede, die spier vesel tipe samestelling sal verander en die direkte impak van die samestelling op kwaliteit eienskappe van vleis. Lammers van die intensiewe produksie sisteem het ‘n betekenisvolle verhoging in uitslagpersentasie, onderhuidse vet dikte (13de rib en 3de/4de lende werwel) en vet ratio (karkas samestelling) getoon. Die vleis van die lammers het meer (p < 0.050) C20:3n6, C20:5n3 en C22:5n3 vetsure bevat asook ‘n hoër n3:n6 ratio gehad. Lammers van die ekstensiewe produksie sisteem het ‘n betekenisvolle hoër slag en koue karkas gewig gehad. Die vleis van die lammers het meer (p < 0.050) mioglobien bevat as intensiewe lammers. Resultate van die studie dui aan dat die vleis van lammer van die intensiewe produksie sisteem meer gunstige sensories karakteristiek produseer in vergelyking met lammers van die ekstensiewe produksie sisteem, asook ‘n betekenisvolle verhoging in sensoriese sagtheid van die Biceps femoris spier. Die Biceps femoris was die spier in die studie wat die meeste geaffekteer was deur die behandeling (produksie sisteme). Die Biceps femoris spier van intensiewe lammers het meer intramuskulêre vet en tipe IIB spier vesels bevat teenoor die Biceps femoris van ekstensiewe lammers wat meer onoplosbare kollageen en tipe I spier vesels bevat het. Gedurende die tekstuur profiel analise (instrumentele sagtheid toets) het die Longissimus dorsi en Semimembranosus van ekstensiewe lammers a hoër kompressie krag vereis, wat aandui dat die spiere taaier is as die ooreenstemmende spiere van intensiewe lammers. Die resultate van die studie voorsien ons met waardevolle insig in die inpak van verskeie produksie sisteme op die kwaliteit van lams vleis. Die afleiding kan gemaak word dat die implementering van intensiewe produksie sisteem die sensoriese kwaliteit van die spiere van Dohne Merino lammers verbeter, veral die sagtheid van die Biceps femoris spier, wat ‘n hoë kommersiële waarde het. Laastens, gesondheidsbewus verbruikers sal verkies om vleis te koop van ekstensiewe lammers weens die gunstige n3:n6 ratio, spier vetinhoud en die minder sigbare vet (onderhuidse vet) op die vleis.

Temos aktualumas. Avininkystė Lietuvoje yra svarbi žemės ūkio sritis. Šio sektoriaus plėtrai šalyje yra palankios gamtinės sąlygos, susiformavusios gyvulių auginimo tradicijos, sukaupta patirtis. Gyvulininkystės sektorius yra daugiašakė ir įvairiapuse produkcija pasižyminti veikla, reikšminga Lietuvos gyventojams daugeliu ekonominių ir socialinių aspektų. Šis sektorius yra reikšmingas, aprūpinant Lietuvos vartotojus įvairiais maisto produktais bei svarbus Lietuvos eksporto šaltinis. Gyvūninės kilmės produktai yra svarbi subalansuotos mitybos dalis. Juose yra daug žmogaus organizmui reikalingų maisto medžiagų, vitaminų ir mineralų. Lietuvos Respublikos žemės ūkis atlieka svarbią ekonominę, socialinę, gamtosauginę ir etnokultūrinę funkciją, todėl laikomas prioritetine ūkio šaka. Jis pajėgus aprūpinti šalies gyventojus visais kokybiškais maisto produktais ir dalį jų eksportuoti. Nors ir lėtai, avininkystės sektorius plečiasi. Auga mėsos paklausa, atsigauna ir vilnos bei kailių perdirbėjai. Vidutinis avių ūkis Lietuvoje, palyginti su vakarų šalimis, dar yra labai mažas. Dauguma augintojų laiko nedaug avių. O tų žmonių, kuriems avininkystė yra verslas, tėra vos kelios dešimtys. Tačiau mažieji augintojai pamažu didina savo bandas. Įdiegus pažangias intensyvaus avių auginimo technologijas, auginant perspektyvias krypties avių veisles, galima tikėtis šio verslo sėkmės. Darbo objektas: skirtingą skaičių avių turintys ūkiai. Darbo tikslas: išanalizuoti ūkio dydžio įtaką avių... [toliau žr. visą tekstą]
Relevance of the thesis. Shepherding has an important place in Lithuania‘s agriculture. There are suitable enviromental conditions, established cattle herding traditions and accumulated experience needed for this sector‘s further development in the country. The area of animal husbandry is activity known for its multisectoral and multifaceted production, many aspects of which has great economical and social significance for Lithuanians. This area is also very significant when providing Lithuanian consumer with eatables, furthermore it is very important branch of Lithuania‘s export. Products of animal origin takes big part in a balanced diet. They contain many components, vitamins and minerals which human body requires daily. Husbandry has important economical, social, enviromental and ethnocultural function in the Republic of Lithuania, thus it has priority in Lithuania‘s economy. It has capability not only to provide quality eatables for citizens, but also to export some. Sheepherding sector is growing, even though the growth rate is not very pronounced. The demand for meat grows; wool and fur processors are recovering. In Lithuania average sheep farm is very small when comparing with farms in other western countries. Most livestock owners don‘t have a lot of sheep. Furthermore, there are only few who make business out of it. However the small farmers seem to be increasing their flocks. If this business were introduced to advanced sheep herding technologies as well as... [to full text]

CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel Superior
O presente estudo foi conduzido objetivando-se avaliar a influÃncia dos nÃveis de inclusÃo e graus de moagem do resÃduo de caju (Anacardium occidentale, L.) sobre o consumo, coeficientes de digestibilidade, parÃmetros de comportamento ingestivo e o pH do lÃquido ruminal de dietas experimentais isoenergÃticas e isoprotÃicas contendo o resÃduo de caju fornecidas a ovinos em terminaÃÃo. Vinte e quatro ovinos foram distribuÃdos em delineamento inteiramente casualizado em esquema fatorial 4 X 2, quatro nÃveis de inclusÃo (11, 21, 28 e 33%) de subproduto de caju em dois graus de moagem (trÃs e 19 mm de diÃmetro da peneira do triturador de grÃos, representando moagem fina e grosseira, respectivamente), em substituiÃÃo ao feno de capim Aruana (Panicum maximum cv. Aruana), milho e torta de algodÃo, perfazendo oito tratamentos experimentais. O consumo, com exceÃÃo das hemiceluloses, e os coeficientes de digestibilidade dos parÃmetros avaliados nÃo foram afetados pelos graus de moagem aplicados ao subproduto de caju. A inclusÃo do subproduto de caju, em dietas para pequenos ruminantes, em atà 33% do total dietÃtico nÃo afeta o consumo. Quando incluso em nÃveis superiores a 21 %, o subproduto de caju pode provocar reduÃÃo nos coeficientes de digestibilidade do EE e FDN dietÃticos. Jà a inclusÃo deste subproduto em nÃveis superiores a 28% à dieta, pode reduzir a digestibilidade da MS, MO, e energia bruta. O tempo gasto com alimentaÃÃo foi reduzido com a inclusÃo do resÃduo em altas proporÃÃes da dieta, entretanto, elevados nÃveis de inclusÃo do resÃduo de caju nÃo promoveram reduÃÃo no tempo gasto com ruminaÃÃo. O pH do lÃquido ruminal foi maior para as dietas com os maiores nÃveis de inclusÃo do resÃduo. Os resultados indicam que o resÃduo de caju pode ser utilizado em dietas para ovinos em terminaÃÃo, nas mesmas condiÃÃes aplicadas neste trabalho, em nÃveis de atà 21%, em ambos os graus de moagem.

The series of experiments described in this thesis were designed to investigate the role of suckling or late weaning in the response of young lambs to nematode infection. All experiments were conducted outdoors with grazing animals and no supplementation but for suckled groups of lambs whose counterparts were weaned to ryegrass – white clover swards. The parasite of interest was mainly Teladorsagia circumcincta solely but with mixed infection of Trichostrongylus colubriformis in one instance. In Chapter 3 (first experiment), the hypothesis that milk per se may have a direct effect on nematode development, rather than an indirect effect through enhancement of host immunity by superior nutrient supply was tested. Sixty, twinborn lambs were used, allocated to one of eight groups formed by either dosing lambs from 42 days of age or not with the equivalent of 1000 or 250 L₃ T. circumcincta larvae d⁻¹ until five days before necropsy, while a twin was either weaned at 39 days of age, suckled as single or twin until necropsy on day 84. The possibility that weaning one of a twin set onto pasture in close proximity to the ewe would cause abnormal ewe and lamb behaviour was tested by replicating the work in twins maintained as twins but in which one twin received equivalent of 250 and the other 1000 L₃ T. circumcincta larvae d⁻¹. This showed no abnormal ewe nursing or lamb suckling behaviour as a result of weaning a twin in a set. Relatively low faecal egg counts (FEC) and a two to three fold lower worm burdens suggest suckling could reduce larval establishment. Inability to detect peripheral titres of immunoglobulins supports this conclusion. An intra worm-population regulation of T. circumcincta, indicated by a pattern of greater egg-laying by a numerically smaller but physiologically better developed nematode population in suckled lambs measured in eggs 'in utero' and worm length made interpretation of FEC difficult. Suckling significantly improved weight gain and carcass weights, but early weaning did not reduce resilience to infection. In Chapter 4 (second experiment), 40 pairs of twin lambs, average age of 39 days, were either infected with the equivalent of 1000 L₃ T. circumcincta larvae d⁻¹ or not, while one twin was weaned and the other allowed to continue suckling. Necropsy was carried out on groups of five and six lambs from each of the uninfected and infected treatments, respectively, at mean age of 84, 112, and on six lambs from each group at 140 days of age. This serial slaughter allowed further confirmation of the hypothesis in Chapter 3 but also investigated the long-term effect of suckling on resistance or resilience of lambs at the trial when immune responses were anticipated to be developing. An in vitro direct larval challenge (IVDC) study, to monitor larval establishment, was carried out on tissue explants from necropsied lambs. Suckled lambs consistently showed lower FEC (P < 0.05) and worm burdens (P < 0.05) at every phase of the trial. Within the infected groups, % in vitro larval rejection suggested earlier immune responses in the weaned lambs by day 84, which was not consistent with lower worm burdens in suckled lambs but appeared similar in the subsequent necropsies. Lambs continued to show better growth due to suckling while weaning did not reduce the resilience of lambs confirming observations in Chapter 3. The immunoglobulin profile suggested the commencement of immune responses in lambs from the period after the 84th day necropsy, with significantly greater (P < 0.01) IgA titre in the infected groups, and the suckled lambs towards the end of the trial on day 140. A vaccinating effect of early exposure to parasites was coincidentally revealed as a result of unintentional pasture larval contamination, seen in suckled non-infected lambs shedding fewer eggs and harbouring fewer worms during the later necropsies compared with their weaned non-infected counterparts. In Chapter 5 (third trial), 93 pairs of twin lambs, 47 pairs of which received a vaccinating mixed infection of T. circumcincta and T. colubriformis larvae (60 L₃ / kg W / d) at ratio 40:60, respectively during the period 36 – 103 days of age, were either weaned early on day 51 or later on day 108. All lambs were drenched on day 108 and groups received challenge infections from day 116, at same rate with the vaccinating infection, or not, which ceased five days before respective necropsies. Necropsies were carried out on selected lambs on days 108, 184 and 218. The direct effect of milk on larval establishment appeared to feature only in the T. circumcincta populations on slaughter day 108. The long-term benefit of late weaning for development of resistance was conditional on lambs receiving the vaccinating infection, and appeared to be more pronounced in the small intestine, reflected by a greater reduction of T. colubriformis populations in that organ than of T. circumcincta populations in the abomasum. A negative consequence of enhanced immune response was the suggestion of an increased metabolic cost in reduced performance of lambs. In conclusion, the work provides support to the hypotheses that: (a.) suckling may reduce the establishment of nematode larvae through the direct effect of milk, (b.) may enhance rapid development of host immunity to infection, and (c.) it further suggests that lack of larval experience during suckling may have long term negative implications for host resistance. Finally, it suggests that milk may play little role in the enhancement of host resilience to infection and, on the contrary, that additional metabolic cost may be associated with a more rapid development of immunity resulting from larval challenge while suckling.

Abstract Birth of offspring of a pre-determined sex using flow cytometrically sorted fresh spermatozoa was first achieved in rabbits by Johnson et al. (1989). Since then offspring have been produced using sex-sorted spermatozoa from several different species (reviewed by Johnson, 2000). Initially, efficiency of the sex-sorting technology was poor with only low numbers of spermatozoa sorted per hour. Thus, the offspring derived from flow cytometrically sorted spermatozoa were produced with the use of artificial reproductive technologies (ART) such as in vitro fertilisation (IVF) and culture (IVC), intracytoplasmic sperm injection (ICSI) and deep artificial insemination (AI) which facilitated low dose insemination of potentially compromised spermatozoa. More recently, the development of high-speed sorters (Johnson and Welch, 1999) has facilitated the production of offspring using conventional AI techniques with low dose inseminates (Seidel et al., 1999) and successful cryopreservation of sorted spermatozoa (Schenk et al., 1999; Johnson et al., 2000; Lindsey et al., 2002; Schenk and DeGrofft, 2003). Increased efficiency of sorting bull spermatozoa has evolved through significant instrumentation and biological developments which have enabled the commercialization of the sperm sexing technology in the dairy industry, although conception rates in cows after low dose AI with sexed frozen-thawed spermatozoa are still lower than after standard frozen semen AI (Seidel et al., 1999). Subsequently, over 20 000 calves of pre-determined sex have been produced from commercially available sex-sorted frozen-thawed bull spermatozoa (Seidel, 2003). However, similar developments have not been made in the sheep industry and were examined in this thesis. In this study, successful cryopreservation of sex-sorted ram spermatozoa and production of offspring of the pre-determined sex (X: 94.4 %; Y: 100 %) was achieved after low dose (2-4 x 106 total) insemination using conventional laparoscopic intrauterine (IU) AI. However, the overall pregnancy rate for ewes inseminated with sex-sorted frozen-thawed spermatozoa was low (25 %) compared to ewes inseminated with a commercial dose (140 x 106 total) of non-sorted frozen-thawed spermatozoa (54 %). Cryopreservation has been found to not only reduce the proportion of motile spermatozoa, but cause the remaining spermatozoa to undergo changes that advance membrane maturation thereby shortening their lifespan, especially after in vivo fertilisation (Gillan and Maxwell, 1999). It was found that sorting prior to cryopreservation accelerated the maturation of sperm membranes and after co-incubation with oviducal cells in vitro, sorted frozen-thawed spermatozoa were released more rapidly than non-sorted (control) frozen-thawed spermatozoa. The potentially reduced lifespan of sorted frozen-thawed spermatozoa, and practical constraints on the number of spermatozoa that can be sorted for an insemination dose, makes insemination close to the site of fertilisation and time of ovulation critical for successful fertilisation. After treatment of ewes with GnRH to increase the precision of insemination in respect to the time of ovulation, there was no difference in pregnancy rate between ewes inseminated before, during or after the assumed time of ovulation. Furthermore, there was no difference in pregnancy rate after IU AI with similar doses of sorted frozen-thawed and non-sorted frozen-thawed spermatozoa in GnRH-treated ewes. The minimum dose of sorted frozen-thawed spermatozoa required for commercially acceptable pregnancy rates determined after IU AI was high (20 x 106 motile). Consequently, alternative methods for efficiently producing large numbers of offspring of a pre-determined sex using flow cytometrically sorted ram spermatozoa were investigated. Ram spermatozoa can be stored for short periods of time in a chilled state (liquid storage) or for an indefinite period of time in a frozen state (frozen storage; Salamon and Maxwell, 2000). The fixed location of the sperm sorter requires the need for transport of semen from the point of collection to the site of sorting and processing, but also from the sperm sorter site to the recipient females under artificial conditions. In this study, ram spermatozoa liquid stored for 24 h prior to sorting were efficiently sorted, frozen, thawed and after in vitro fertilisation and culture produced a high proportion of grade 1 blastocysts. Similarly, spermatozoa stored at reduced temperatures after sorting maintained high sperm quality for up to 6 days. Furthermore, frozen-thawed spermatozoa from rams and some non-human primates were successfully prepared for sorting and efficiently sorted producing spermatozoa with high quality in vitro parameters. The quality of frozen-thawed ram spermatozoa after sorting was such that successful re-cryopreservation after sorting was possible. Low numbers of frozen-thawed sorted and re-frozen and thawed spermatozoa were optimal for IVF and a high proportion of grade 1 in vitro embryos of a pre-determined sex were produced. These embryos were either transferred immediately or vitrified prior to transfer, extending the application of the sperm sexing technology further. The birth of lambs of pre-determined sex after transfer of both fresh and vitrified embryos derived from frozen-thawed sorted spermatozoa was achieved. The findings in this thesis suggest that sorted frozen-thawed ram spermatozoa may have more advanced membrane maturation state than non-sorted frozen-thawed spermatozoa, resulting in a decreased fertilizing lifespan in the female reproductive tract. Despite this, the use of sexed ram spermatozoa in a number of physiological states (fresh, liquid, frozen) with several different ARTs is possible in producing significant numbers of offspring of a pre-determined sex. Improved efficiency in both sperm sexing and associated reproductive technologies is required for commercialization to be achieved in the sheep industry.

Com este estudo objetivou-se avaliar ovelhas da raça Morada Nova (MN) e Santa Inês (SI) quanto à infecção parasitária e desempenho reprodutivo e produtivo quando acasaladas ou cruzadas com reprodutores da raça Dorper (D), assim como, o desempenho e as características de carcaça e da carne dos cordeiros Morada Nova (MM), Santa Inês (SS) e de seus meio sangue ½ Dorper x ½ Morada Nova (MD) e ½ Dorper x ½ Santa Inês (SD) terminados em confinamento. Foram utilizadas 51 ovelhas (MN) com 33,1 ± 4,98 kg de peso e 52 ovelhas (SI) com 51,8 ± 7,07 kg, todas multíparas com idades entre 2 a 4 anos. As ovelhas permaneceram em pastagem de Panicum maximum (cultivar Aruana) e no terço final de gestação e na lactação foram mantidas em baias coletivas recebendo silagem de milho ad libitum e 400 g/animal/dia de concentrado. Após a desmama, foram utilizados 32 cordeiros sendo 8 MM (peso 15,0 ± 1,0 Kg), 8 SS (peso 18,4 ± 1,0 Kg), 8 MD (peso 16,1 ± 1,0 Kg) e 8 SD (peso 21,3 ± 1,0 Kg) com aproximadamente 70 dias de idade e terminados em confinamento com dieta composta de 40 % de silagem de milho e 60 % de concentrado e abatidos aos 35 kg de peso aproximadamente. Em ambas as raças maternas a infecção parasitária foi caracterizada pela predominância de parasitas do gênero Haemonchus, que se agravou no pré e pós-parto com as ovelhas MN capazes de manter a infecção mais baixa aos 30 dias pós-parto. O grau de infecção parasitária não foi suficiente para alterar negativamente as variáveis hematológicas que se mantiveram dentro da normalidade para a espécie, com algumas diferenças entre as raças de acordo com as datas de coleta. Ambas as raças maternas apresentaram bom desempenho reprodutivo, produzindo crias ao nascimento e à desmama mais pesadas quando cruzadas com reprodutores Dorper e Fêmeas MN cruzadas com reprodutores Dorper produzindo a desmama, crias com pesos semelhantes a ovelhas SI acasaladas. Cordeiros cruzados SD e MD apresentam desempenho e características de carcaça semelhantes, com maior deposição de tecido em regiões de maior valor comercial quando comparados aos cordeiros puros. Quanto a carne, não foi identificada diferença entre os grupos estudados para as características de cor, maciez e suculência, mas os cordeiros cruzados apresentaram carne com menor quantidade de gordura, com os cordeiros SD expondo uma gordura com melhor perfil nutricional para o consumo humano do que de cordeiros MD
The objectives of this study were to evaluate the parasitic infection; reproductive and productive performance of Morada Nova (MN) and Santa Inês (SI) sheep crossed with Dorper rams; and to evaluate productive performance; carcass and meat characteristics of Morada Nova (MM) and Santa Inês (SS) lambs and that of the crossbred ½ Dorper x ½ Morada Nova (MD) and ½ Dorper x ½ Santa Inês (SD) lambs, finished in feedlot system. Fifty one MN sheep (33,1 ± 4,98 kg initial body weight - BW) and 52 SI sheep (51,8 ± 7,07 kg BW), all multiparous, aging from 2 to 4 years old were used. The sheep were kept in Panicum maximum cv. Aruana pasture and from the final third of gestation up to lactation period they were housed in collective pens, receiving corn silage ad libitum and 400 g/animal/day of concentrate. After weaning, 32 lambs, 8 MM (15,0 ± 1,0 Kg BW), 8 SS (18,4 + 1,0 Kg BW), 8 MD (16,1 ± 1,0 Kg BW) and 8 SD (21,3 ± 1,0 Kg BW) aging about 70 days old, finished in feedlot system and fed on a 40:60 corn silage and concentrate diet were slaughtered around the body weight of 35 Kg. In both maternal breeds the parasitic infection was characterized by the predominance of Hamonchus genus parasites, and it has increased in pre and postpartum periods; the MN sheep were capable of maintaining reduced parasitic infection at 30 days after giving birth. The parasitic infection has not affected blood parameters, which were maintained in the reference range of the species, with some differences being observed between breeds according to blood collection dates. Both maternal breeds presented good reproductive performance, producing lambs that presented increased birth and weaning weight when crossed with Dorper ram; MN sheep when crossed with Dorper ram have produced lambs that presented weaning weights similar to that of lambs produced by SI sheep when mated with SI ram. Crossbred lambs SD and MD presented similar productive performance and carcass characteristics, with increased tissue deposition in more commercially appreciated areas when compared with pure breed lambs. In the meat characteristics evaluations, no differences were observed between the studied groups for meat color, softness and juiciness but the crossbred lambs produced meat with reduced fat content, with SD lambs presenting fat profile more suitable for human consumption than MD lambs

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Universidade Estadual Paulista (UNESP)
O experimento foi desenvolvido no setor de Ovinocultura da Universidade de Marília com o objetivo de avaliar os efeitos dos níveis de suplementação alimentar com ração contendo 25% de PB e 3,18 Mcal EM/kg/MS para cordeiras criadas em pastagem com comedouro privativo sobre o peso e desempenho em distintas idades, bem como o inicio da puberdade e desempenho reprodutivo. Foram utilizadas 21 cordeiras Suffolk oriundas de parto simples, divididas em 3 lotes experimentais, sem e com suplementação, alimentadas do nascimento ao desmame em comedouros privativos com 2 níveis de ingestão de concentrado (300 e 600 g/dia) fornecido uma vez ao dia com o registro das sobras diárias. As cordeiras foram identificadas, pesadas ao nascimento e a cada 30 dias, permanecendo com suas mães até o desmame, pré-estabelecido em 60 dias. Não houve diferenças significativas para peso e ganho médio de peso diário aos 30 dias de idade, demonstrando que os níveis de ingestão não influenciaram os parâmetros analisados. O peso e ganho médio de peso diário foram influenciados pelo nível de suplementação alimentar. O lote com consumo de 600 gramas mostrou desempenho superior aos outros dois lotes aos 60 e 120 dias de idade. Para os lotes de 300 gramas e sem suplementação não houve diferença para os parâmetros analisados. A disponibilidade de 600 gramas diários de concentrado contendo 25% de PB e 3,18 Mcal de EM/kg/MS para as cordeiras até o desmame promoveu maior ganho médio de peso diário aos 60 e 120 dias de vida e melhor desempenho reprodutivo no 2º ano de cobertura.
The experiment was developed in the Sheep Production Department at University of Marília, wich aim was to evaluate the effects of the levels of the food supplies (without supplies, 300, 600 g of concentrate/day) with concentrate containing 25% of CP and 3,18 Mcal ME/kg/DM for females lambs raised in pasture with creep feeding about weight and acting in different ages, as well as the beginning of puberty and reproductive performance. The subjects were 21 female lambs Suffolk breed proceeding from simple birth which were divided into 3 experiment lots, fed from birth up to weaning in creep feeding with 2 levels of ingestion of concentrated (without supplied, 300 and 600 g/concentrate/day) given once a day by recording daily leftovers. The female lambs were identified weighed soon after birth and then, weighed every 30 days, remaining with their mothers up to weaning, pre established for 60 days. There was no significant difference for weight and medium gain of weight daily at 30 days of age, showing that the levels of ingestion did not influence the analyzed parameters. The weight and medium gain of daily weight were influenced for the level of food supplied, the lot consuming of 600 g showed performance greater than the other 2 lots at 60 and 120 days of age. For the lots of 300 g and without supplied there was no significant differences for the analyzed parameters. The availability of 600 g concentrated daily containing 25% of CP and 3,18 Mcal of ME/kg/DM for the female lambs up to weaning resulted in higher medium gain of weight daily at age of 60 and 120 days, as well as better reproductive performance in the 2º year of animal copulation.

Resumo: O experimento foi desenvolvido no setor de Ovinocultura da Universidade de Marília com o objetivo de avaliar os efeitos dos níveis de suplementação alimentar com ração contendo 25% de PB e 3,18 Mcal EM/kg/MS para cordeiras criadas em pastagem com comedouro privativo sobre o peso e desempenho em distintas idades, bem como o inicio da puberdade e desempenho reprodutivo. Foram utilizadas 21 cordeiras Suffolk oriundas de parto simples, divididas em 3 lotes experimentais, sem e com suplementação, alimentadas do nascimento ao desmame em comedouros privativos com 2 níveis de ingestão de concentrado (300 e 600 g/dia) fornecido uma vez ao dia com o registro das sobras diárias. As cordeiras foram identificadas, pesadas ao nascimento e a cada 30 dias, permanecendo com suas mães até o desmame, pré-estabelecido em 60 dias. Não houve diferenças significativas para peso e ganho médio de peso diário aos 30 dias de idade, demonstrando que os níveis de ingestão não influenciaram os parâmetros analisados. O peso e ganho médio de peso diário foram influenciados pelo nível de suplementação alimentar. O lote com consumo de 600 gramas mostrou desempenho superior aos outros dois lotes aos 60 e 120 dias de idade. Para os lotes de 300 gramas e sem suplementação não houve diferença para os parâmetros analisados. A disponibilidade de 600 gramas diários de concentrado contendo 25% de PB e 3,18 Mcal de EM/kg/MS para as cordeiras até o desmame promoveu maior ganho médio de peso diário aos 60 e 120 dias de vida e melhor desempenho reprodutivo no 2º ano de cobertura.
Abstract: The experiment was developed in the Sheep Production Department at University of Marília, wich aim was to evaluate the effects of the levels of the food supplies (without supplies, 300, 600 g of concentrate/day) with concentrate containing 25% of CP and 3,18 Mcal ME/kg/DM for females lambs raised in pasture with creep feeding about weight and acting in different ages, as well as the beginning of puberty and reproductive performance. The subjects were 21 female lambs Suffolk breed proceeding from simple birth which were divided into 3 experiment lots, fed from birth up to weaning in creep feeding with 2 levels of ingestion of concentrated (without supplied, 300 and 600 g/concentrate/day) given once a day by recording daily leftovers. The female lambs were identified weighed soon after birth and then, weighed every 30 days, remaining with their mothers up to weaning, pre established for 60 days. There was no significant difference for weight and medium gain of weight daily at 30 days of age, showing that the levels of ingestion did not influence the analyzed parameters. The weight and medium gain of daily weight were influenced for the level of food supplied, the lot consuming of 600 g showed performance greater than the other 2 lots at 60 and 120 days of age. For the lots of 300 g and without supplied there was no significant differences for the analyzed parameters. The availability of 600 g concentrated daily containing 25% of CP and 3,18 Mcal of ME/kg/DM for the female lambs up to weaning resulted in higher medium gain of weight daily at age of 60 and 120 days, as well as better reproductive performance in the 2º year of animal copulation.
Orientador: Ciniro Costa
Coorientador: Cledson Augusto Garcia
Banca: Paulo Roberto de Lima Meirelles
Banca: Katia de Oliveira
Banca: Rodolfo Claudio Spers
Banca: Wagner Reis
Doutor

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
Two studies were conducted to evaluate effects of corn grain replacement with passion fruit by-product (PFB) in finishing lambs on feed intake, feedlot performance, carcass traits and digestibility. In study 1, 20 Morada Nova ram lambs (15,4±1,4kg BW) were used in a completely randomized design with 4 treatments: isonitrogenous (19% CP) experimental diets contained 30% Tifton-85 bermudagrass hay and 70% concentrate (soybean meal, wheat meal, corn and 0, 25, 50, or 75% PFB). Over a period of 21 d, lambs were housed in digestibility cages (14 d adaptation and 7 d data collection) and DM, CP and NDF digestibilities estimated by total fecal collection technique. In the study 2, 32 Morada Nova ram lambs (22.4 ± 3.2 kg BW) were housed in individual pens and assigned to a randomized block design (initial BW) and fed the same diets of study 1 for 78 d (14 d adaptation and 64 d data collection). DM and nutrient intakes, average daily gain (ADG) and gain to feed (G:F) were evaluated and after slaughter (32 kg), yields of hot carcass (HCY) and cold carcass (CCY) were calculated. Data from study 1 were analyzed using the procedure of SISVAR and means were compared with Tukey test (P < 0.05). For the study 2, data were analyzed with MIXED procedure with each animal as the experimental unit, and model effects included block and treatment. DM and CP digestibilities were not affected by PFB when it was added up to 50% (74.98 ± 2.0 and 77.38 ± 2.8%, respectively; P > 0.05). However, DM and CP digestibilities decreased in 75% PFB diet (69.7 ± 0.7 and 72.5 ± 1.1%, respectively). NDF digestibility was unaffected by treatments (P > 0.05), averaging 49.4 ± 3.4%. There were no differences in DM and digestible nutrient intakes (P > 0.05). No differences were evidenced (P > 0.05) in ADG (152 ± 0.03 g), G:F (0.147 ± 0.01 kg), HCY (46.6 ± 1.0%) and CCY (45.0 ± 1.0%). The data indicate that although passion fruit by-product decreases diets DM and CP digestibility, it is a suitable replacement for corn grain in diets for feedlot lambs when used at up to 75%
Dois estudos foram realizados para avaliar os efeitos da substituição do milho com subproduto do maracujá (SPM) na terminação de cordeiros sobre a digestibilidade, consumo, desempenho em confinamento e características de carcaça. No primeiro estudo, 20 cordeiros Morada Nova (15,4±1,4kg PC) foram usados em um delineamento inteiramente casualizado com 4 tratamentos: as dietas experimentais isonitrogenadas (19% PB) continham 30% feno Tifton-85 e 70% de concentrado (farelo de soja , farinha de trigo, milho e 0, 25, 50, ou 75% SPM. Durante um período de 21 dias, os cordeiros foram alojados em gaiolas de digestibilidade (adaptação 14 dias e 7 dias de colheita de dados) sendo a digestibilidade da MS, PB e FDN estimados pela técnica de coleta total de fezes. No segundo estudo, 32 cordeiros Morada Nova (22,4 ± 3,2 kg PC) foram alojados em baias individuais e distribuídos em delineamento em blocos casualizados, sendo alimentados com as mesmas dietas do estudo 1 por 78 dias (adaptação 14 dias e 64 dias de colheita de dados). Os consumos de matéria seca (MS) e dos nutrientes digestivos, ganho médio diário (GMD) e eficiência alimentar (EA), rendimentos de carcaça quente (RCQ) e de carcaça fria (RCF) foram avaliados e após o abate foram calculados os rendimentos de carcaça quente e fria. Os dados do primeiro estudo foram analisados utilizando o procedimento do SISVAR e as médias comparadas pelo teste de Tukey (P <0,05). Já os dados do segundo estudo foram analisados com o procedimento MIXED quando cada animal foi considerado uma unidade experimental, e no modelo foram incluídos os efeitos dos blocos e dos tratamentos. A digestibilidade da MS e da PB não foram afetadas pela SPM, quando ela foi adicionada até 50% (74,98 ± 2,0 e 77,38 ± 2,8%, respectivamente; P> 0,05). No entanto, a digestibilidade da MS e PB diminuíram com 75% de SPM na dieta (69,7 ± 0,7 e 72,5 ± 1,1%, respectivamente). A digestibilidade da FDN não foi afetada pelos tratamentos (P> 0,05), com média de 49,4 ± 3,4%. Não houve diferenças nos consumos de MS e de nutrientes digestíveis (P> 0,05). Nenhuma diferença foi evidenciada (P> 0,05) no GMD (152 ± 0,03 g), EA (0,147 ± 0,01 kg), RCQ (46,6 ± 1,0%) e RCF (45,0 ± 1,0%). Os dados indicam que, apesar do subproduto do maracujá diminuir a digestibilidade da MS e da PB das dietas, ele é um substituto adequado ao grão de milho em dietas para cordeiros confinados quando usado em até 75%

Experimento I: Foram utilizadas 60 borregas da raça Santa Inês com o objetivo de avaliar os efeitos de três taxas de crescimento até os 7 meses de idade. Os tratamentos foram delineados visando obter alta taxa de crescimento (ATC), moderada taxa de crescimento (MTC) e baixa taxa de crescimento (BTC). Foram avaliados o consumo de matéria seca, o ganho de peso corporal e as concentrações séricas de progesterona para a detecção da idade à puberdade. Foram verificados efeitos lineares (p<0,01) para o peso corporal e metabólico, sendo os maiores valores encontrados para os animais do tratamento ATC. Efeito linear (p<0,01) foi verificado para o ganho médio diário (GMD) sendo de 0,182; 0,156 e 0,136 kg/dia para os tratamentos ATC, MTC e BTC respectivamente. Borregas pertencentes ao tratamento ATC apresentaram maior conversão alimentar sendo os valores para o tratamento ATC de 6,1; MTC de 7,1 e BTC de 9,2 kg MS/ kg de ganho de peso. Verificou-se diferença (p<0,01) quanto a porcentagem de animais que atingiram a puberdade sendo o tratamento MTC com o maior número de borregas púberes até os 7 meses de idade (60%), seguida dos tratamentos ATC (45%) e BTC (15%)com peso médio de 39,3 kg de peso corporal, sendo 70% do peso adulto. Experimento II: As borregas utilizadas no experimento 1 com 37 Kg de PC entraram em estação de monta e após o parto receberam uma única dieta, sendo blocadas de acordo com o peso e dias de lactação. Observou-se efeito quadrático (p<0,01) na produção de leite em 3h (137,9; 150,1 e 104,4 g), efeito quadrático (p<0,05) para LCG (167,2; 178,9 e 129,4) e efeito quadrático (p<0,03) LCGP (216,5; 140,5 e 162,7). Os teores de gordura (9,8; 8,9 e 8,3%) e de proteína (4,2; 4,2 e 4,6 apresentaram efeitos lineares sendo (p=0,01) para gordura e (p<0,01) para proteína. Experimento III: Os objetivos deste experimento foram avaliar o efeito da inclusão de bagaço de cana-de-açúcar in natura (BIN) sobre o consumo e a digestibilidade aparente dos nutrientes, balanço de nitrogênio e os parâmetros ruminais de cordeiros Santa Inês. Quatro cordeiros providos de cânula ruminal com peso corporal (PC) médio inicial de 30kg foram alojados individualmente em gaiolas para ensaios de metabolismo. O tratamento controle positivo (CONT) consistia de uma ração de alto concentrado contendo de 10% de feno de coastcross (Cynodon sp.) na MS, sendo os demais tratamentos níveis crescentes de BIN em 10, 20 e 30% da MS, constituindo os tratamentos 10BC, 20BC e 30BC. As rações experimentais foram isonitrogenadas (13,75±0,25% PB). Não verificou-se efeito de tratamento (p>0,05) sobre o consumo de MS, MO, e PB em kg/dia e g/kg de PC 0,75; apenas sobre consumo de FDN com efeito linear (p< 0,01). O balanço de nitrogênio, assim como a concentração de acetato, propionato, butirato, concentração total de AGCC, amônia no fluido ruminal e a de digestibilidade aparente da MS, MO, PB e FDN não foram afetados pelos tratamentos.
Trial I: Sixty Santa Ines ewe lambs were used to evaluate the effects of three growing rates until 7 months of age. Treatments were defined to achieve high (HGR), moderate (MGR) and low (LGR) growing rates. The dry matter intake and average daily gain (ADG) were evaluated, well as serum levels of progesterone in order to detect the age of puberty. Linear effects (P<0.01) to body weight (BW) with values being 59.5, 61.4, and 58.0 to HGR, MGR and LGR, respectively. Linear effects (P<0.01) was also observed for average daily gain with values being 0.182, 0.156, and 0.136 kg/day, for HGR, MGR and LGR, respectively. The feed:gain ratio showed a linear effects (p<0.02) according to raw sugarcane bagasse inclusion in diet with values being 6.1, 7.1 (M) and 9.2 kgDM/kg BW for HGR, MGR and LGR, respectively. Linear effects (p<0.01) was observed for the percentage of animals of ewe lambs the reached puberty at 7 months of age, showing highest values for MGR (60%), followed by HGR (45%) and LGR (15%) treatment. Trial II: The same ewe lambs of Experiment 1 were bred at 37 kg of BW and after lambing they received a unique diet. The ewe lambs were blocked according to body weight and days in milking. According to the energy density increase in the diet, quadratic effects (p<0.01) was observed on milk production recorded in a 3-hour interval (137.9; 150.1 and 104.4 g), fat corrected milk (167.2, 178.9 and 129.4 g) and fat and protein corrected milk (216.5, 140.5, 162.7g). Fat (9.77, 8.92 and 8.35%) and protein (4.2, 4.2, and 4.6%) showed linear effects (P=0.01) for fat and (P<0.01) for protein. Trial III: The aim of this study was to evaluate the inclusion of raw sugarcane bagasse (RSB) on dry matter intake and apparent digestibility of nutrients, nitrogen balance and ruminal parameters of Santa Ines ram lambs. Four ruminally fistulated ram lambs averaging 30 kg of BW were placed in metabolism crates. The control treatment (CONT) consisted of a high concentrate diet with 10% of coastcross (Cynodon sp.) hay in the dietary DM and the others treatments consisted of 10, 20 and, 30% of RBS in the dietary DM. The diets were formulated to provide similar concentration of crude protein (13.75±0.25%). No effects were observed for DMI, OM, and CP in kg/day and g/kg of BW0.75. Linear effects (p<0.02) was observed for NDF intake according RBS inclusion. Variables, as well as total SCFA, acetate, propionate, and butyrate concentrations. Ruminal ammonia and apparent nutrient digestibility also did not differ among treatments.