Academic literature on the topic 'Total digestible nutrients'

In Indonesia, forage is difficult to obtain in the dry season, while the agricultural waste very abundant and potentially pollute the environment. Use of agricultural waste as feed animal is very advantage to obtain cattle nutrients need and alleviate pollution. An experiment was conducted to evaluate the nutrient quality of fermented complete feed based on soybean straw (CFS), compared with forage (F) or forage and concentrate with 4:1 ratio (FC). Proximate analysis was conducted to three kind of feed, then nutrients digestibility were conducted by in-vitro analyzed. Each kind of feed consisted of 4 replicates. The results showed that CFS had higher ash and crude protein content and less crude fiber than FS and F. CFS had dry matter digestibility (DMD), organic matter digestibility (OMD) and total digestible nutrients (TDN) significantly (p< 0.05) higher than F but not significantly different with FC. There are not significantly different of NH3 production among the three kinds of feed. The conclusion was CFS had highest nutrient content. CFS and FC had digestible nutrient that higher than F. The quality of CFS can still be improved by adding N digestible for rumen microbe growth.Key words: complete feed, soybean straw, nutrient digestibility

The purpose of this study is to evaluated the relationship of energy consumption (total digestible nutrients), intake protein and month of lactation with milk production on dairy cattle in Semarang Regency. The materials used was 40 dairy cattle between 1-9 month of lactation. It were grouped into 3 groups of month lactation including group 1 (1-3 month), group 2 (4-6 month) and group 3 (7-9 month). The measured variables were dry matter consumption, crude protein, and total digestible nutrients as independent variables and milk production as a fixed variable. The effect of independent variables on fixed variables was tested using correlation test and linear regression. The result showed that milk production of each group 1,2 and 3 was 12.12, 9.40, and 7.73 liters / day. The crude protein content and total digestible nutrients ration ranged between 12-13.7% and 62-66%. The consumption of crude protein and total digestible nutrients had no apparent correlation with milk production in dairy cattle in Semarang Regency, but milk production was strongly influenced by lactation (p <0.01). Correlation value (r) between lactation month with milk production showed moderate relationship (r = 0,55) with regression equation Y = 13.258-0,717X, that the milk production will decrease equal to 0,717 liter every month. The conclusion of this study is consumtion of protein and energy is not correlated with dairy milk production in Semarang Regency. Lack of consumption of crude protein and total digestible nutrients in early lactation leads to lower production presistence than normal milk production patterns.

The objective of the present study was to evaluate the nutritional value of elephant-grass silages containing annato byproduct. Twenty intact rams were distributed in a complete randomized block design with five diets (0; 4; 8; 12 and 16% annato byproduct in the silage) and four replications and used to estimate the intake, apparent nutrient digestibility, content of total digestible nutrients and nitrogen balance. The addition of annato byproduct raised the intakes of dry matter (DM), organic matter (OM), crude protein (CP), neutral detergent fiber (NDF), acid detergent fiber (ADF), ether extract (EE), total carbohydrates (TC), non-fibrous carbohydrates (NFC) and total digestible nutrients (TDN), in body weight (%BW) and in metabolic weight (g kg-1BW0.75). The digestibilities of DM (55.95%), OM (58.19%), CP (45.34%), NDF (52.79%), ADF (45.79%), EE (34.96%) and NFC (99.86%) were not influenced by the addition of annato byproduct. The inclusion of annato byproduct in elephant-grass silage increased digestibility of total carbohydrates, the TDN content and the nitrogen balance. The aditions of annato byproduct at levels up to 16% of the elephant grass silage natural matter improves nutrient intake and nitrogen balance.

The objective of this study was to evaluate the effect of manure at saline soil on forage production, quality and livestock carrying capacity of P. maximum and S. grandiflora. The research was conducted on moderately saline soil at Rembang Regency, Central Java Province, Indonesia.Randomized complete block design was used as design experiment. The treatments were different dosage of manure as organic amendment (0, 10 and 20 tonnes/ha). Forage crops were P. maximum and S. grandiflora that planted monoculture or mixed-cropping. Parameters measured were dry matter (DM) production, ash, crude protein, crude fibre, ether extract, total digestible nutrients. P. maximum was cut eight times, S. grandiflora was cut six times during one year. The result showed that the highest total dry matter production of mixed cropping P. maximum and S. grandiflora was available at moderately saline soil with application 20 ton/ha manure. Total production of dry matter, crude protein and total digestible nutrient available at application 20 ton/ha manure were 29131 kg/ha/year; 3722 kg/ha/year and 17718 kg/ha/year, respectively. Carrying capacity based on dry matter, crude protein and total digestible nutrients were 10.8 AU/ha/year; 13.6 AU/ha/year and 11.3 AU/ha/year, respectively. In conclusion, application of 20 ton/ha manure at saline soil increased production, crude protein and carrying capacity.

Penelitian ini bertujuan untuk mengetahui pengaruh penambahan suplementasi herbal (tepung daun katuk dan tepung jintan hitam), penambahan mineral Sulfur Proteinat (S-Proteinat) serta penambahan kombinasi herbal dan mineral terhadap kecernaan serat dan Total Digestible Nutrient (TDN) pakan sapi perah secara in vitro. Rancangan penelitian yang digunakan adalah Rancangan Acak Lengkap (RAL) dengan empat perlakuan dan empat ulangan. Perlakuan yang diterapkan adalah T0 = Ransum Kontrol, T1 = T0 + kombinasi herbal (0,50% tepung daun katuk + 0,50% tepung jintan hitam), T2 = T0 + mineral (0,25% S-Proteinat) dan T3 = T1 + mineral (0,25% S-Proteinat). Ransum kontrol terdiri atas hijauan rumput gajah dan konsentrat komersial. Parameter yang diamati adalah kecernaan Neutral Detergen Fibre (KcNDF), kecernaan Serat Kasar (KcSK) dan nilai Total Digestible Nutrient (TDN). Hasil penelitian menunjukkan bahwa perlakuan pemberian suplementasi tepung daun katuk dan tepung jintan hitam, mineral S-Proteinat serta kombinasi kedua herbal dan mineral S-Proteinat tidak berpengaruh nyata (P>0,05) terhadap nilai KcNDF, KcSK dan TDN. Disimpulkan bahwa pemberian suplementasi herbal tepung daun katuk 0,50% BK pakan dan tepung jintan hitam 0,50% BK pakan, mineral S-Proteinat 0,25% BK pakan serta kombinasi kedua herbal dan mineral S-Proteinat belum mampu meningkatkan nilai kecernaan NDF dan SK serta nilai TDN pakan.Kata kunci : kecernaan serat, total digestible nutrients, in vitro, herbal, mineral.

Penelitian ini bertujuan untuk mengetahui kecernaan bahan kering, bahan organik, lemak kasar dan Total Digestible Nutrients (TDN) beberapa hijauan secara in vitro. Penelitian ini dilaksanakan pada bulan September 2018 – Januari 2019 di Laboratorium Ilmu Nutrisi dan Pakan, Fakultas Peternakan dan Pertanian, Universitas Diponegoro, Semarang. Penelitian ini menggunakan rancangan acak lengkap (RAL) dengan 8 jenis hijauan pakan sebagai perlakuan masing-masing 3 ulangan. Parameter yang diamati kecernaan bahan kering, bahan organik, lemak kasar dan TDN. Hasil penelitian menunjukkan bahwa berbagai jenis hijauan menghasilkan nilai kecernaan dan TDN yang berbeda (P<0,05). Kesimpulan hasil penelitian ini adalah kecernaan bahan kering, bahan organik dan lemak kasar dipengaruhi oleh kandungan nutrien dalam bahan pakan, sedangkan nilai TDN berkorelasi dengan nilai kecernaan nutrien dalam bahan pakan.

The fractional rate of digestion as compared with the rate of passage can determine the extent of digestion in the digestive tract and the amount of potentially digestible matter escaping digestion (Van Soest, 1982). The lower the rate of digestion or the higher the rate of passage, the more nutrients escape digestion. The effect of rate of passage is higher for food components with slow rates of digestion such as neutral-detergent fibre (NDF) (Mertens, 1985). Increasing feeding level is associated with higher rate of passage, lower residence time in the rumen and decreased digestibility of nutrients. Digestibility depression is considered in several energy evaluation systems (van Es et al., 1978; Moe, 1981; Agricultural and Food Research Council, 1993 etc.) although most of the systems use a standard percentage discounting energy value, regardless of foods or nutrient components. Studies (Tyrell and Moe, 1975) showed that digestibility depression is higher for cell wall than cell solubles, whilst El Khidir and Thomsen (1983) reported that digestibility depression of cell walls was responsible for proportionately 0-7 of the observed decrease in digestibility. Mertens (1985) reported that energy discount factors can be related to NDF content and total digestible nitrogen value of foods. Ørskov (1996) recommended prediction of food potential of both energy value and intake from degradation characteristics.

SUMMARY It was evaluated the effect of feed supplementation at 0.4; 0.8 and 1.2% of body weight (BW) on intake and digestibility of crossbred goats finished on caatinga, in relation to crossbred goats not supplemented (0.0% of BW). Thirty-two crossbred, Anglo-Nubian goats were used, eight months old and with body weight of 18 ± 2.5 kg, organised into randomised blocks, which were kept on 37 hectares of caatinga from 7 h to 16 h. Intake of dry matter, organic matter, crude protein, ether extract, neutral and acid detergent fibre, total carbohydrates and total digestible nutrients was influenced (P<0.05) by the levels of feed supplementation, with linear increases of 202.31; 179.42; 25.05; 11.83; 35.79; 12.27; 142.63 and 166.79 g animal-1 day-1 respectively. There was a substitution effect (P<0.05) on dry matter intake when using feed supplementation at 0.7% BW. Feed supplementation resulted in positive linear effect (P<0.05) for digestibility of dry matter, organic matter, crude protein, ether extract, total carbohydrates, total digestible-nutrient content and digestible energy, with an increase of 17.15; 16.64; 19.07; 44.74; 15.15 and 17.56% for dry matter, and 0.69 Mcal kg-1 of dry matter respectively. Final body weight, total gain and average daily gain, showed a linear increase (P<.005) of 2.60, 3.09 and 0.036 kg per percentage point of each additional level of supplement. Feed supplementation increases the intake and digestibility of total dry matter and nutrients, a fact that makes greater performance possible, and recommends use up to a level of 0.7% BW to avoid any substitution effect.

Abstract Objective was to determine the effects of supplementing corn-soybean meal-based diets with a multi-enzyme on growth performance and apparent total tract digestibility (ATTD) of nutrients in growing pigs. A total of 276 pigs (BW = 33.99 ± 4.3 kg) were housed by sex in 45 pens of 6 or 7 pigs and fed 5 diets (9 pens/diet) in a randomized complete block design. Diets were positive control (PC); and negative control 1 (NC1) or negative control 2 (NC2) without or with multi-enzyme. The multi-enzyme used supplied at least 1,250, 860, 4,600, and 1,000 units of xylanase, β-glucanase, arabinofuranosidase and phytase per kilogram of diet, respectively. The PC was adequate in all nutrients according to NRC (2012) recommendations and had greater digestible P content than NC1 diet or NC2 diet by 0.134 percentage points. The NC1 diet had lower NE and digestible AA content than PC diet by 3%. The NC2 diet had lower NE and digestible AA content than PC diet by 5%. The diets were fed in 4 phases based on BW; Phase 1: 34–50 kg, Phase 2: 50–75 kg, Phase 3: 75–100 kg, and Phase 4: 100–120 kg. Nutrient digestibility was determined at the end of Phase 1. Overall (34–120 kg BW), pigs fed the PC and NC1 diets did not differ in ADG and ADFI. Pigs fed NC2 diet had lower (PPPP > 0.10). Supplemental multi-enzyme increased (P = 0.047) the ATTD of GE for NC2 diet. In conclusion, the NE and digestible AA and P can be lowered by ≤ 5% in multi-enzyme-supplemented diets without effects on growth performance pigs.

One hundred and eight Holstein dairy heifers were divided into two weight blocks based on beginning body weight (E = < 182 kg, light, > 270 kg, heavy). Heifers within weight blocks were randomly assigned to one of five treatments. Treatments consisted of three levels of NDF (35%, 45%, 55%) at 100% ofNRC TDN recommendation, and three levels of TDN (85%, 100%, 115 of NRC) at 45% NDF for light heifers. For heavy heifers, treatments consisted of three levels of NDF (40%, 50%, 60%) at 100% NRC TDN, and three treatments with similar levels of TDN at 50% NDF. Heifers were fed total mixed rations of corn silage, alfalfa haylage, ground orchardgrass hay, soybean meal, high moisture corn and a mineral mix formulated for 0.68 kg ADG. Mean gains (kg/d) were 1.07 and .96 for the light and heavy blocks, respectively. DMI as a percent of BWT differed across NDF levels for light heifers (3r'= 2.96, 2.56, 2.57, 2.57, and 2.87 % of BWT for the low, med., high NDF, and low, high TDN treatments, respectively). Heavy heifer DMI% did not differ (.Â¥= 2.45, 2.40, 2.24, 2.15, and 2.42 % ofBWT for low, med., and high NDF, and low, high TDN treatments, respectively). Equations to predict DMI were developed using intake information from this and a previous study. Backward stepwise regression was utilized to generate a simplified model. Model selected was: DMI (kg/d) = -5.9781 + (2.2120E-05 * BWTSQ) - (5.5527 * GAIN) + (2.7837 * GAINSQ) + (0.4668 * NDF) + (5.3930 * NDFSQ) + (0.03285 * DM) + 1 (7.7859E-03 * BWT * GAIN);11 = 514, rz = .67.
Master of Science

O trabalho foi conduzido na região da Campanha do RS, no município de Quaraí, com objetivo de avaliar a composição florística e bromatológica de pastagem natural submetida ou não à utilização de insumos, e os reflexos sobre o comportamento ingestivo e desempenho animal. Os tratamentos foram pastagem natural (PN), pastagem natural adubada (PNA) e melhorada com adubação + sobressemeadura de espécies hibernais (PNM). O delineamento experimental foi blocos ao acaso, com três repetições, sendo os dados submetidos à análise de variância considerando as estações do ano como medidas repetidas no tempo. Os dados florísticos foram submetidos à análise multivariada. Foram utilizados novilhos da raça Angus em fase de terminação. O estudo da vegetação revelou grande riqueza florística, representada por 264 espécies distribuídas em 161 gêneros e 48 famílias. As famílias mais ricas em contribuição de espécies foram Poaceae, Asteraceae e Cyperaceae com 48, 15 e 13 espécies, respectivamente. Entre as espécies com mais de 1% de valor de importância, 13 eram estivais e dez hibernais, demonstrando um grande equilíbrio entre essas. A maior digestibilidade da forragem dos tratamentos melhorados no inverno e primavera justificou-se pela contribuição em valor de importância nestas épocas, das espécies nativas Andropogon lateralis Nees, Stipa setigera J. Presl, Piptochaetium stipoides (Trin. & Ruprecht.) Hackel var. stipoides, Paspalum notatum Alain, Mnesithea selloana (Hack.) Koning & Sosef, Briza subaristata Lam., Paspalum dilatatum Poir. e da espécie hibernal exótica Lolium multiflorum Lam. A relação entre o tempo de permanência e tempo de pastejo nas áreas de vegetação é de 73,6; 74,7; 34,0 e 51,5%, para Várzea úmida, Várzea seca + Encosta, Sombra e Topo, respectivamente. As variáveis FDNcp, relação NDT:PB, DIVMO e MS da composição química da forragem aparentemente consumida pelos animais explicaram 80% do ganho médio diário. A utilização da adubação ou sua associação com introdução de espécies proporcionam maior contribuição de espécies hibernais no período inverno-primavera em pastagem natural, contribuindo para uma melhor distribuição estacional da produção de forragem. As estações do ano têm marcada influência sobre a composição química da forragem, podendo ser parcialmente estabilizada pelo uso de insumos, notadamente a fertilização, pelo seu efeito na participação de espécies hibernais. Nesse tipo fisionômico de pastagem natural, o repertório de atividades de comportamento ingestivo de novilhos de corte em pastagem natural não é modificado pelos níveis de insumos aplicados.
This work was conducted in Quaraí, Campanha region of Rio Grande do Sul, Brazil, with the aim to evaluate the floristic and chemical composition of natural grassland submitted to the application of inputs, and effects on ingestive behavior and animal production. Treatments were natural grassland (PN), natural grassland fertilized (PNA) and improved natural grassland with fertilization and over seeding of cool season species (PNM). The experimental design was a randomized complete blocks with three replicates. Data were submitted to analyses of variance considering seasons of the year as repeated measurements on time. The floristic data were submitted to multivariate analysis. Aberddeen Angus steers in finishing phase were used. The vegetation study showed high floristic diversity, with 264 plant species distributed in 161 genera and 48 families. The families with higher contribution of species were Poaceae, Asteraceae and Cyperaceae with 48, 15 and 13 plant species, respectively. Considering species with more than 1% of importance value, 13 and ten were warm and cool season plants, respectively, what show a high equilibrium between them. The higher forage digestibility of the improved treatments on winter and spring was justified by the contribution in importance value of natural species as Andropogon lateralis Nees, Stipa setigera J. Presl, Piptochaetium stipoides (Trin. & Ruprecht.) Hackel var. stipoides, Paspalum notatum Alain, Mnesithea selloana (Hack.) Koning & Sosef, Briza subaristata Lam., Paspalum dilatatum Poir. and of the cool season specie Lolium multiflorum Lam. The relation between the permanence time and grazing time on vegetation areas was 73.6; 74.7; 34.0 and 51.5% to wet lowland, dry lowland + downhill, shadow and top, respectively. Variables NDFap, relation TDN:CP, IVOMD and DM of chemical composition of forage apparently intaked by animals explained 80% of average daily gain. The fertilization or its association with the specie‟s over sowing provided bigger contribution of cool season species in natural grasslands, contributing to a better seasonal distribution of forage production. Seasons influences markedly chemical composition of forage, which could be partially stabilized by using inputs, as fertilization, by its effect on the increase of cool season species. In these natural grasslands beef steers‟ activities of ingestive behavior were not modified by the applied input levels.

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This study aimed to evaluate intake, apparent digestibility of nutrients and nitrogen balance (NB) of diets containing babassu mesocarp bran (BMB) in replacement of elephant grass silage (0, 21, 38, 62 and 78%). Twenty sheep were placed in metabolism crates and allotted to a completely randomized design with four replicates. Were collected and recorded food intake and excretion of feces and urine. The intakes of dry matter (DM), organic matter (OM), crude protein (CP), ash, neutral detergent fibrous (NDF), acid detergent fibrous (ADF), hemicellulose and total carbohydrates were not affected by experimental diets. Change was observed in the intakes of non fibrous carbohydrates (NFC) and reduced intake of ether extract (EE) as % of live weight (%LW) and grams per unit of metabolic weight (g/UMW). The total digestible nutrients TDN intake had a quadratic response with maximum points at 37.3 and 37.9% of BMB when expressed in % LW and g/UMW, respectively. The apparent digestibilities of OM, NDF, ADF, CP and NFC reduced to the extent that the BMB has increased in the diets. The digestibility of DM, EE, and NFC had a quadratic response, where the maximum digestibility of DM was estimated at 10% BMB. TDN decreased 0.28% for each percentage point of inclusion in the diets of BMB. The BMB use reduces the fibrous fractions digestibility, but increases the NFC and TDN intake, indicating that this byproduct can be used as an energy source for ruminant diets. Note: Thesis w/seven chapters. Presented summary and abstract of the 2nd chapter
Objetivou-se avaliar consumo, digestibilidade aparente de nutrientes e balanço de nitrogênio (BN) de dietas contendo farelo de mesocarpo de babaçu (FMB) em substituição à silagem de capim elefante (0; 21; 38; 62 e 78%). Utilizaram-se 20 ovinos alojados em gaiolas metabólicas individuais e distribuídos em delineamento inteiramente casualisado com quatro repetições. Foram coletados e registrados o consumo de alimentos e excreções de fezes e urina. Os consumos de matéria seca (MS), matéria orgânica (MO), proteína brutua (PB), cinza, fibra em detergente neutro (FDN), fibra em detergente ácido (FDA), hemicelulose e carboidratos totais não foram influenciados pelas dietas experimentais. Foi observada alteração nos consumos de carboidratos não fibrosos (CNF) e redução nos consumos de extrato etéreo (EE) em % do PV e em gramas por unidade de tamanho metabólico (g/UTM). O consumo de nutrientes digestíveis totais (NDT) teve comportamento quadrático com pontos de máximo em 37,3 e 37,9% de FMB expressos em %PV e g/UTM, respectivamente. As digestibilidades aparentes da MO, FDN, FDA, PB e CNF reduziram na medida em que o FMB aumentou nas dietas. A digestibilidade da MS, EE e CNF tiveram comportamento quadrático, em que a máxima digestibilidade da MS foi estimada com 10% de FMB. O NDT reduziu 0,28% para cada ponto percentual de inclusão de FMB nas dietas. O uso do FMB reduz a digestibilidade de frações fibrosas, contudo aumenta o consumo de CNF e o consumo de NDT, o que indica que esse subproduto pode ser utilizado como fonte energética para dietas de ruminantes. OBS: Tese c/ sete capítulos. Apresentado resumo e abstract do 2° capítulo.

Bones are multifunctional passive organs of movement that supports soft tissue and directly attached muscles. They also protect internal organs and are a reserve of calcium, phosphorus and magnesium. Each bone is covered with periosteum, and the adjacent bone surfaces are covered by articular cartilage. Histologically, the bone is an organ composed of many different tissues. The main component is bone tissue (cortical and spongy) composed of a set of bone cells and intercellular substance (mineral and organic), it also contains fat, hematopoietic (bone marrow) and cartilaginous tissue. Bones are a tissue that even in adult life retains the ability to change shape and structure depending on changes in their mechanical and hormonal environment, as well as self-renewal and repair capabilities. This process is called bone turnover. The basic processes of bone turnover are: • bone modeling (incessantly changes in bone shape during individual growth) following resorption and tissue formation at various locations (e.g. bone marrow formation) to increase mass and skeletal morphology. This process occurs in the bones of growing individuals and stops after reaching puberty • bone remodeling (processes involve in maintaining bone tissue by resorbing and replacing old bone tissue with new tissue in the same place, e.g. repairing micro fractures). It is a process involving the removal and internal remodeling of existing bone and is responsible for maintaining tissue mass and architecture of mature bones. Bone turnover is regulated by two types of transformation: • osteoclastogenesis, i.e. formation of cells responsible for bone resorption • osteoblastogenesis, i.e. formation of cells responsible for bone formation (bone matrix synthesis and mineralization) Bone maturity can be defined as the completion of basic structural development and mineralization leading to maximum mass and optimal mechanical strength. The highest rate of increase in pig bone mass is observed in the first twelve weeks after birth. This period of growth is considered crucial for optimizing the growth of the skeleton of pigs, because the degree of bone mineralization in later life stages (adulthood) depends largely on the amount of bone minerals accumulated in the early stages of their growth. The development of the technique allows to determine the condition of the skeletal system (or individual bones) in living animals by methods used in human medicine, or after their slaughter. For in vivo determination of bone properties, Abstract 10 double energy X-ray absorptiometry or computed tomography scanning techniques are used. Both methods allow the quantification of mineral content and bone mineral density. The most important property from a practical point of view is the bone’s bending strength, which is directly determined by the maximum bending force. The most important factors affecting bone strength are: • age (growth period), • gender and the associated hormonal balance, • genotype and modification of genes responsible for bone growth • chemical composition of the body (protein and fat content, and the proportion between these components), • physical activity and related bone load, • nutritional factors: – protein intake influencing synthesis of organic matrix of bone, – content of minerals in the feed (CA, P, Zn, Ca/P, Mg, Mn, Na, Cl, K, Cu ratio) influencing synthesis of the inorganic matrix of bone, – mineral/protein ratio in the diet (Ca/protein, P/protein, Zn/protein) – feed energy concentration, – energy source (content of saturated fatty acids - SFA, content of polyun saturated fatty acids - PUFA, in particular ALA, EPA, DPA, DHA), – feed additives, in particular: enzymes (e.g. phytase releasing of minerals bounded in phytin complexes), probiotics and prebiotics (e.g. inulin improving the function of the digestive tract by increasing absorption of nutrients), – vitamin content that regulate metabolism and biochemical changes occurring in bone tissue (e.g. vitamin D3, B6, C and K). This study was based on the results of research experiments from available literature, and studies on growing pigs carried out at the Kielanowski Institute of Animal Physiology and Nutrition, Polish Academy of Sciences. The tests were performed in total on 300 pigs of Duroc, Pietrain, Puławska breeds, line 990 and hybrids (Great White × Duroc, Great White × Landrace), PIC pigs, slaughtered at different body weight during the growth period from 15 to 130 kg. Bones for biomechanical tests were collected after slaughter from each pig. Their length, mass and volume were determined. Based on these measurements, the specific weight (density, g/cm3) was calculated. Then each bone was cut in the middle of the shaft and the outer and inner diameters were measured both horizontally and vertically. Based on these measurements, the following indicators were calculated: • cortical thickness, • cortical surface, • cortical index. Abstract 11 Bone strength was tested by a three-point bending test. The obtained data enabled the determination of: • bending force (the magnitude of the maximum force at which disintegration and disruption of bone structure occurs), • strength (the amount of maximum force needed to break/crack of bone), • stiffness (quotient of the force acting on the bone and the amount of displacement occurring under the influence of this force). Investigation of changes in physical and biomechanical features of bones during growth was performed on pigs of the synthetic 990 line growing from 15 to 130 kg body weight. The animals were slaughtered successively at a body weight of 15, 30, 40, 50, 70, 90, 110 and 130 kg. After slaughter, the following bones were separated from the right half-carcass: humerus, 3rd and 4th metatarsal bone, femur, tibia and fibula as well as 3rd and 4th metatarsal bone. The features of bones were determined using methods described in the methodology. Describing bone growth with the Gompertz equation, it was found that the earliest slowdown of bone growth curve was observed for metacarpal and metatarsal bones. This means that these bones matured the most quickly. The established data also indicate that the rib is the slowest maturing bone. The femur, humerus, tibia and fibula were between the values of these features for the metatarsal, metacarpal and rib bones. The rate of increase in bone mass and length differed significantly between the examined bones, but in all cases it was lower (coefficient b <1) than the growth rate of the whole body of the animal. The fastest growth rate was estimated for the rib mass (coefficient b = 0.93). Among the long bones, the humerus (coefficient b = 0.81) was characterized by the fastest rate of weight gain, however femur the smallest (coefficient b = 0.71). The lowest rate of bone mass increase was observed in the foot bones, with the metacarpal bones having a slightly higher value of coefficient b than the metatarsal bones (0.67 vs 0.62). The third bone had a lower growth rate than the fourth bone, regardless of whether they were metatarsal or metacarpal. The value of the bending force increased as the animals grew. Regardless of the growth point tested, the highest values were observed for the humerus, tibia and femur, smaller for the metatarsal and metacarpal bone, and the lowest for the fibula and rib. The rate of change in the value of this indicator increased at a similar rate as the body weight changes of the animals in the case of the fibula and the fourth metacarpal bone (b value = 0.98), and more slowly in the case of the metatarsal bone, the third metacarpal bone, and the tibia bone (values of the b ratio 0.81–0.85), and the slowest femur, humerus and rib (value of b = 0.60–0.66). Bone stiffness increased as animals grew. Regardless of the growth point tested, the highest values were observed for the humerus, tibia and femur, smaller for the metatarsal and metacarpal bone, and the lowest for the fibula and rib. Abstract 12 The rate of change in the value of this indicator changed at a faster rate than the increase in weight of pigs in the case of metacarpal and metatarsal bones (coefficient b = 1.01–1.22), slightly slower in the case of fibula (coefficient b = 0.92), definitely slower in the case of the tibia (b = 0.73), ribs (b = 0.66), femur (b = 0.59) and humerus (b = 0.50). Bone strength increased as animals grew. Regardless of the growth point tested, bone strength was as follows femur > tibia > humerus > 4 metacarpal> 3 metacarpal> 3 metatarsal > 4 metatarsal > rib> fibula. The rate of increase in strength of all examined bones was greater than the rate of weight gain of pigs (value of the coefficient b = 2.04–3.26). As the animals grew, the bone density increased. However, the growth rate of this indicator for the majority of bones was slower than the rate of weight gain (the value of the coefficient b ranged from 0.37 – humerus to 0.84 – fibula). The exception was the rib, whose density increased at a similar pace increasing the body weight of animals (value of the coefficient b = 0.97). The study on the influence of the breed and the feeding intensity on bone characteristics (physical and biomechanical) was performed on pigs of the breeds Duroc, Pietrain, and synthetic 990 during a growth period of 15 to 70 kg body weight. Animals were fed ad libitum or dosed system. After slaughter at a body weight of 70 kg, three bones were taken from the right half-carcass: femur, three metatarsal, and three metacarpal and subjected to the determinations described in the methodology. The weight of bones of animals fed aa libitum was significantly lower than in pigs fed restrictively All bones of Duroc breed were significantly heavier and longer than Pietrain and 990 pig bones. The average values of bending force for the examined bones took the following order: III metatarsal bone (63.5 kg) <III metacarpal bone (77.9 kg) <femur (271.5 kg). The feeding system and breed of pigs had no significant effect on the value of this indicator. The average values of the bones strength took the following order: III metatarsal bone (92.6 kg) <III metacarpal (107.2 kg) <femur (353.1 kg). Feeding intensity and breed of animals had no significant effect on the value of this feature of the bones tested. The average bone density took the following order: femur (1.23 g/cm3) <III metatarsal bone (1.26 g/cm3) <III metacarpal bone (1.34 g / cm3). The density of bones of animals fed aa libitum was higher (P<0.01) than in animals fed with a dosing system. The density of examined bones within the breeds took the following order: Pietrain race> line 990> Duroc race. The differences between the “extreme” breeds were: 7.2% (III metatarsal bone), 8.3% (III metacarpal bone), 8.4% (femur). Abstract 13 The average bone stiffness took the following order: III metatarsal bone (35.1 kg/mm) <III metacarpus (41.5 kg/mm) <femur (60.5 kg/mm). This indicator did not differ between the groups of pigs fed at different intensity, except for the metacarpal bone, which was more stiffer in pigs fed aa libitum (P<0.05). The femur of animals fed ad libitum showed a tendency (P<0.09) to be more stiffer and a force of 4.5 kg required for its displacement by 1 mm. Breed differences in stiffness were found for the femur (P <0.05) and III metacarpal bone (P <0.05). For femur, the highest value of this indicator was found in Pietrain pigs (64.5 kg/mm), lower in pigs of 990 line (61.6 kg/mm) and the lowest in Duroc pigs (55.3 kg/mm). In turn, the 3rd metacarpal bone of Duroc and Pietrain pigs had similar stiffness (39.0 and 40.0 kg/mm respectively) and was smaller than that of line 990 pigs (45.4 kg/mm). The thickness of the cortical bone layer took the following order: III metatarsal bone (2.25 mm) <III metacarpal bone (2.41 mm) <femur (5.12 mm). The feeding system did not affect this indicator. Breed differences (P <0.05) for this trait were found only for the femur bone: Duroc (5.42 mm)> line 990 (5.13 mm)> Pietrain (4.81 mm). The cross sectional area of the examined bones was arranged in the following order: III metatarsal bone (84 mm2) <III metacarpal bone (90 mm2) <femur (286 mm2). The feeding system had no effect on the value of this bone trait, with the exception of the femur, which in animals fed the dosing system was 4.7% higher (P<0.05) than in pigs fed ad libitum. Breed differences (P<0.01) in the coross sectional area were found only in femur and III metatarsal bone. The value of this indicator was the highest in Duroc pigs, lower in 990 animals and the lowest in Pietrain pigs. The cortical index of individual bones was in the following order: III metatarsal bone (31.86) <III metacarpal bone (33.86) <femur (44.75). However, its value did not significantly depend on the intensity of feeding or the breed of pigs.