Proportion Of Empty Body Weight Research Articles

The Effects of Single or Combined Supplementation of Probiotics and Prebiotics on Growth Performance, Dietary Energetics, Carcass Traits, and Visceral Mass in Lambs Finished under Subtropical Climate Conditions

Simple SummaryConcern about the use of antimicrobial compounds in livestock production has promoted research of “generally recognized as safe” additive alternatives. Probiotics (living microorganisms) and prebiotics (certain type of carbohydrates derived from yeast) have been shown to alleviate the negative effects of stress and boost immunity, thereby enhancing efficiency of energy utilization. In some regions (i.e., tropical and arid zones), livestock experience adverse climatic conditions, including elevated ambient temperature and humidity, which affect their productivity. Supplementation with probiotics and prebiotics may help to alleviate these adverse effects. In the present study, supplemental probiotics or/and prebiotics improved dietary energetic efficiency in lambs finished under subtropical climatic conditions. The combination of probiotics with prebiotics reinforced this positive effect.The aim of this trial was to test the effects of the use of eubiotics (pro- and prebiotics) alone or in combination in the diet of lambs finished under subtropical climate conditions. For this purpose, 40 Pelibuey × Katahdin lambs (29.5 ± 4.8 kg initial live weight) were used in a 93 day growth-performance experiment. Dietary treatments consisted of a cracked corn-based finishing diet supplemented with (1) no eubiotics (control), (2) 3 g of probiotics (live Saccharomyces cerevisiae, SC), (3) 3 g of prebiotics (mannan oligosaccharide plus b-glucans, MOS), and (4) a combination of 1.5 g of SC and 1.5 g of MOS (SC+MOS). Throughout the study, the average temperature humidity index (THI) was 78.60. Compared to controls, supplementation with SC or MOS, alone did not affect average daily gain (ADG), but enhanced feed efficiency by 5.6% and 6.9% (gain-to-feed ratio, G:F) and dietary net energy by 4.6% and 5.9%, respectively. Compared to controls, SC+MOS enhanced ADG (10%), G:F (9.5%), and dietary net energy (7.2%). Lambs fed SC+MOS had also greater ADG, G:F, and dietary net energy compared to lambs fed SC alone. When compared to MOS, the combination enhanced ADG (10.4%, p = 0.04). This effect could be attributed to the increased dry matter intake (7.6%, p = 0.06), as neither G:F nor dietary energy was significantly affected. Compared with controls and SC, supplementation with MOS alone and SC+MOS increased kidney–pelvic–heart fat, while SC supplementation tended (p = 0.08) to reduce 4.1% the relative intestinal mass (as a proportion of empty body weight) when compared to controls. Treatment effects on the other carcass measures were not significant. In the present study, supplemental probiotics and/or prebiotics improved dietary energetic efficiency in lambs finished under subtropical climatic conditions. The combination of probiotics with prebiotics reinforced this positive effect.

The effects of feeding a standardized mixture of essential oils vs monensin on growth performance, dietary energy and carcass characteristics of lambs fed a high-energy finishing diet

Thirty-six Pelibuey × Katahdin crossbred intact male lambs (28.5 ± 3.5 kg) were used in a 56-d experiment in a randomized complete block design to evaluate the effects of a standardized mixture of essential oils (EO) versus monensin sodium (MON) on growth performance, dietary energy, and carcass characteristics. Lambs were fed a corn-based finishing diet (13.8 % CP and 2.14 Mcal NEm/kg DM) supplemented with: 1) no additive (Control), 2) 30 mg MON/lamb, and 3) 150 mg EO/lamb. Water consumption of EO and Control lambs was not different. In contrast, lambs fed MON consumed 18.1 % less (P < 0.01) water than Controls and EO groups. Compared to Controls, EO improved (P < 0.05) gain efficiency, estimated dietary net energy (NE). Compared to MON, supplemental EO increased (P < 0.05) dry matter intake (DMI), average daily gain (ADG) and gain efficiency, and tended (P = 0.09) to increase estimated dietary NE. Compared to Controls, lambs fed MON decreased DMI and ADG but without showing difference on gain efficiency and estimated dietary NE. With the exception of carcass weight (lambs fed MON had lower hot carcass weight than Control and EO), there were no treatments effects on carcass composition. Compared with Controls, EO and MON supplementation decreased relative weights (as a proportion of empty body weight) of intestine and omental fat. Compared with MON, EO decreased relative weight of mesenteric fat. We conclude that compared with Control (non-supplemented) lambs, supplemental EO enhances feed efficiency, and dietary net energy. Compared with MON, supplemental EO enhances ADG. However, effects of MON and EO on feed efficiency and dietary net energy are not appreciable different. Supplemental EO did not negatively affect carcass characteristics or visceral organ mass. As such, supplemental EO is a viable alternative to the antibiotic monensin for enhancement of feed efficiency of finishing feedlot lambs.

Relationship between feed efficiency and slaughter traits of French Charolais bulls.

Improving feed efficiency is of interest to French beef producers so as to increase their profitability. To enable this improvement through selection, genetic correlations with production traits need to be quantified. The objective of this study was to estimate the genetic parameters for growth, feed efficiency (FE), and slaughter performance of young beef bulls of the French Charolais breed. Three feed efficiency criteria were calculated: residual feed intake (RFI), residual gain (RG), and ratio of FE. Data on feed intake, growth, and FE were available for 4,675 Charolais bulls tested in performance test stations and fed with pelleted diet. Between 1985 and 1989, 60 among 510 of these bulls were selected to procreate one generation of 1,477 progeny bulls which received the same pelleted diet at the experimental farm in Bourges. In addition to feed intake, growth, and FE traits, these terminal bulls also had slaughter traits of carcass yield, carcass composition, and weight of visceral organs collected. Genetic parameters were estimated using linear mixed animal models. Between performance test bulls and terminal bulls, the genetic correlation of RFI was 0.80 ± 0.18; it was 0.70 ± 0.21 for RG and 0.46 ± 0.20 for FE. For carcass traits, RFI was negatively correlated with carcass yield (-0.18 ± 0.14) and muscle content (-0.47 ± 0.14) and positively with fat content (0.48 ± 0.13). Conversely, RG and FE were positively correlated with carcass yield and muscle content and negatively with fat content. For the three FE criteria, efficient animals had leaner carcass. For visceral organs (as a proportion of empty body weight), RFI was genetically correlated with the proportions of the 5th quarter (0.51 ± 0.17), internal fat (0.36 ± 0.14), abomasum (0.46 ± 0.20), intestines (0.38 ± 0.17), liver (0.36 ± 0.16), and kidneys (0.73 ± 0.11). Conversely, RG and FE were negatively associated with these traits. The high-energy expenditure associated with the high-protein turnover in visceral organs may explain this opposite relationship between FE and the proportion of visceral organs. Selection for final weight and RFI increased growth and FE in progeny, and also improved carcass yield and muscle content in the carcass. To conclude, determinations of growth and feed intake in performance test stations are effective to select bulls to improve their growth, FE, and muscle content in carcass.

Evaluation of sulphur amino acid requirement of male Korean native ducklings from hatch to 21 day of age

ABSTRACT1. A dose-response experiment was conducted with male Korean native ducklings (KND) to evaluate the total sulphur amino acid (TSAA) requirement from hatch to 21 d of age.2. A completely randomised design with 7 dietary TSAA concentrations (0.62%, 0.65%, 0.68%, 0.71%, 0.74%, 0.77% and 0.80%) were used with 6 replications per treatment.3. Body weight (BW) and feed intake were measured weekly to calculate average daily gain (ADG), average daily feed intake (ADFI) and feed conversion ratio (FCR). One duckling per pen (n = 6) was killed by cervical dislocation to weigh empty body and drumsticks at the conclusion of experiment.4. BW was improved significantly with increasing TSAA content, in a non-linear manner. A significant decrease of FCR was shown with increasing TSAA contents. TSAA requirement was determined by taking a mean value after fitting the data to both a linear-plateau and a quadratic-plateau model. Estimated TSAA requirements were 0.70%, 0.70%, 0.66% and 0.70% for the maximum BW, ADG and ADFI and for the minimum FCR, respectively. Increasing TSAA content improved quantity of full body weight (FBW), empty body weight (EBW) and drumstick weight (DSW), but there was no effect on proportion of DSW in relation to EBW and proportion of EBW to FBW.5. In conclusion, the growth of male KND during 1 to 21 d of age was improved with increasing TSAA content, suggesting optimal TSAA requirements estimated by two analysis models.

Características da carcaça e dos componentes não carcaça de cordeiros oriundos de parto simples ou duplo

Um experimento foi conduzido com o objetivo de avaliar as características da carcaça e dos componentes não carcaça de cordeiros nascidos de parto simples ou duplo. Dezesseis cordeiros mestiços Texel × Ile de France, machos não castrados, foram desmamados aos 56 dias de idade e abatidos com aproximadamente 28kg de peso corporal. Imediatamente após o abate, cada componente corporal foi pesado separadamente, sendo as carcaças avaliadas após 24 horas de refrigeração a 2°C. Os cordeiros oriundos de parto simples apresentaram superioridade no peso e nos rendimentos da carcaça, além de maior área de olho de lombo. Por outro lado, proporcionalmente ao peso de corpo vazio, o rúmen é maior em cordeiros nascidos de parto duplo, o que resulta incremento da proporção de conteúdo gastrintestinal ao abate. Os resultados deste estudo indicam que, quando abatidos a um mesmo peso, cordeiros oriundos de parto simples possuem carcaças de melhor qualidade, em comparação a cordeiros nascidos de parto gemelar.

Effects of feeding different levels of chromium-enriched live yeast in hairy lambs fed a corn-based diet: effects on growth performance, dietary energetics, carcass traits and visceral organ mass

Forty Pelibuey × Kathdin lambs (35.5 ± 0.4 kg) were used in a 56-day feeding experiment to assess the effects of feeding different levels of chromium-enriched live yeast (Cr-YC) on growth performance, dietary energetics, carcass traits and visceral organ mass. The Cr-YC source contained 5.5 × 109 colony forming units (CFU) and 0.40 mg of Cr per gram. Treatments consisted of a dry rolled corn-based finishing diet supplemented with 0, 1, 2 or 3 g Cr-YC/lamb.day. Total daily dosages were: 5.5 × 109 CFU and 0.4 mg; 1.1 × 1010 CFU and 0.8 mg Cr, and 1.65 × 1010 CFU and 1.2 mg Cr for supplementation levels of 1, 2 or 3 g Cr-YC/lamb.day, respectively. There were no treatments effects on dry matter intake. As the level of Cr-YC supplementation increased, average daily gain, gain to feed and dietary net energy were linearly increased, and observed/expected dry matter intake was linearly decreased. Chromium-enriched live yeast supplementation increased empty bodyweight (EBW), gastrointestinal fill and full viscera weight, but did not influence organ weights as a proportion of EBW (g/kg EBW). Cr-YC level did not affect carcass length, backfat thickness, kidney, pelvic and heart fat or body wall thickness, but increased hot carcass weight and longissimus muscle area. In general, treatment effects on percentage yield of wholesale cuts (tissue weight as a percentage of cold carcass weight) were small. However, Cr-YC decreased percentage flank. Chromium-enriched yeast supplementation enhances growth rate, longissimus muscle area, and dietary energetic efficiency in finishing feedlot lambs.

Postweaning growth of the non-carcass components of Texel crossbred lambs

Twenty 11/16 Texel x 5/16 Ile de France crossbred lambs were slaughtered at different body weights to evaluate the growth of their non-carcass components. Animals were weaned at 42 days of age (15.9 ± 2.1 kg of body weight), housed in individual stalls, and fed ad libitum. After ten days of an experimental adaptation period, 5 lambs were slaughtered. The remaining lambs were randomly assigned to one of three following slaughter weights: 25, 30 or 35 kg of body weight at fast. At slaughter, all body components were individually weighed and expressed as percentage of the empty body weight. To determine allometric growth of individual components, the exponential equation Y = aXb was logarithmically transformed and used. Proportions of feet and head decreased, while wool proportion increased linearly as slaughter weight increased. Greater fat deposition in viscera (kidney and mesenteric fat) was observed for lambs slaughtered at more elevated body weights. Growth rate of small intestine was lower than that of the empty body (b = 0.39), and it decreased linearly as a proportion of empty body weight with advancing maturity. Growth rates of both liver and large intestine were isogonics (b = 0.90 and 1.08, respectively), i.e., similar to the empty body weight. On the other hand, rumen presented late growth (b = 1.37), and its proportion was lower only for the lambs slaughtered at weaning (1.58% of EBW). Once increased slaughter weights result in higher deposition of nutrients on body parts that are not intended to consumption, maximum slaughter weight of 11/16 Texel x 5/16 Ile de France crossbred lambs is recommended to be at 30 kg of body weight.

Órgãos vitais e trato gastrintestinal de vacas de descarte mestiças Charolês x Nelore abatidas com pesos distintos

Objetivou-se estudar o desenvolvimento dos órgãos vitais e do trato gastrintestinal de vacas de descarte mestiças provenientes da segunda (G2 - 3/4Charolês (C) 1/4Nelore (N) e 3/4NC) e terceira geração (G3 - 5/8CN e 5/8NC) do cruzamento rotativo Charolês × Nelore terminadas em confinamento e abatidas com 465 (T465), 507 (T507) ou 566 kg (T566). Os animais apresentaram, em média, ao início do confinamento, 8,5 anos, 388,6 kg e 2,35 pontos de escore corporal. A dieta, com relação volumoso:concentrado de 48:52, continha 12,5% de PB e 2,99 Mcal de ED/kg de MS. Entre os órgãos, o fígado apresentou maior desenvolvimento. O pulmão e o baço desenvolveram até os animais atingirem 507 kg, reduzindo aos 566 kg. O aumento do peso de abate conferiu menor participação relativa do conjunto dos órgãos vitais e trato gastrintestinal no peso vivo e no corpo vazio. Animais da terceira geração do cruzamento rotativo Charolês × Nelore apresentaram maior peso de rúmen-retículo e estômago (14,29 vs 12,30 kg e 24,43 vs 22,28 kg, respectivamente) em relação àqueles da segunda geração. Entretanto, quando o peso dos órgãos foi corrigido para peso vivo e peso de corpo vazio, somente o rúmen-retículo foi maior na terceira geração. Maior participação de sangue Charolês no genótipo conferiu maior volume de sangue, desenvolvimento dos pulmões e do conjunto dos órgãos vitais em relação ao corpo vazio.

Órgãos internos e trato gastrintestinal de novilhos de gerações avançadas do cruzamento rotativo entre as raças Charolês e Nelore terminados em confinamento

Foram avaliados os efeitos de heterose e de grupo genético nos órgãos internos e no trato gastrintestinal de novilhos puros (Charolês - C e Nelore - N) e cruzados da segunda (G2) (3/4C 1/4N e 3/4N 1/4C), terceira (G3) (5/8C 3/8N e 5/8N 3/8C) e quarta (G4) (11/16C 5/16N e 11/16N 5/16C) gerações de cruzamento terminados em confinamento e abatidos com 23 meses de idade. Os animais cruzados da G2, G3 e G4 foram, respectivamente, 14,95; 17,25 e 18,46% superiores aos puros quanto ao peso de corpo vazio (PCVZ). A heterose para o rendimento de carcaça fria em relação ao PCVZ (RCFCVZ) foi positiva em todas as gerações. Os mestiços apresentaram menor peso relativo (ao PCVZ) de coração, pulmões e rins, de modo que a heterose foi significativa para peso de coração (-18,29%) e rins (-14,29%) na G3 e para pulmões (-13,45%) na G4. Novilhos mestiços apresentaram valores inferiores à média dos puros para todos os componentes do trato gastrintestinal quando o peso destes componentes foi expresso em relação a 100 kg de PCVZ ou de peso vivo ao abate (PVA), com exceção do rúmen na G2. A heterose retida foi positiva e significativa para PCVZ, RCFCVZ e para peso absoluto do fígado. Entretanto, foi negativa para a quantidade de sangue para os pesos de coração, intestino delgado + grosso e trato gastrintestinal quando expressos em relação a 100 kg de PCVZ e de PVA. Entre os animais puros, os novilhos Nelore tiveram maior RCFCVZ (57,09 vs 61,64%). O peso absoluto de rúmen, abomaso, intestino delgado + grosso e o trato gastrintestinal foram maiores nos novilhos Charolês em relação aos Nelore, o que também foi observado quando estes componentes foram expressos em relação ao PCVZ e PVA, com exceção para o intestino grosso + delgado. Estas diferenças explicam, em parte, o maior rendimento de carcaça dos novilhos Nelore.

Use of active substances of plant origin in chicken diets based on maize and locally grown cereals

1. A total of 336 Hubbard Hi-Y broiler hybrids were fed from d 1–41 on diets based on maize or wheat and barley which were supplemented (or not) with 100 mg/kg plant extract consisting of capsaicin, cinnamaldehyde and carvacrol. 2. Body weight was not enhanced, but feed conversion improved by 4·2% on the maize diet and 2·0% on the wheat and barley diet. 3. Plant extract addition enhanced the breast muscle proportion of empty body weight by 1·2% in comparison to control birds. 4. The apparent ileal digestibility of nutrients (crude protein, fibre and amino acids) was not significantly better in birds fed on supplemented diets than in the control group. 5. Reduction of E. coli, Clostridium perfringens and fungi and increase of Lactobacillus spp. were observed in the 41-d-old chickens from the supplemented groups. 6. An increase in the lipase activity in pancreas and intestine wall was found in older birds fed on the plant extract supplemented diets.

Effects of dietary protein content and food intake on carcass characteristics and organ weights of growing Iberian pigs

AbstractThe effects of dietary protein content and level of feeding on carcass characteristics and organs weight were evaluated in 72 male castrated Iberian pigs growing from 15 to 50 kg live weight. Animals were offered six diets providing 223, 192, 175, 156, 129 and 101 g crude ideal protein (CP) (N × 6·25) per kg dry matter (DM) and 14·64, 14·14, 14·37, 14·80, 15·36 and 15·53 MJ metabolizable energy (ME) per kg DM, respectively. Each diet was offered at three levels of feeding : 0·60, 0·80 and 0·95 × ad libitum intake. Mean values of protein, fat, ash and water contents in the carcass determined at 50 kg live weight were 130, 378, 28·2 and 458 g/kg, respectively, with a small but significant effect of CP content of the diet on carcass composition (P &lt;0·001 to P &lt;0·01) favouring both protein and fat content on decreasing dietary protein level. Protein deposition (PD) in the eviscerated carcass reached a maximum value when the diet containing 129 g CP per kg DM was offered (54·6 g/day at the highest feeding level). Nitrogen (N) retention in the carcass represented 70·9% of whole-body N retention and the efficiency of this process (carcass N retention : N intake) increased with declining dietary protein content (P &lt;0·001). Carcass energy retention increased significantly with decreasing dietary CP content (P &lt;0·001) and with feeding level (P &lt;0·001). Raising energy intake resulted in a significant increase on total weight of viscera as proportion of empty body weight (P &lt;0·001). Decreasing the CP content in the diet resulted in a lower proportional shoulder weight (P &lt;0·01) meanwhile the proportion of ham decreased significantly (P &lt;0·05) with increase in feeding level. The proportionate weights of dissectable fat in the shoulder and of intermuscular and subcutaneous fat in the ham increased significantly (P &lt;0·05 and P &lt;0·001) in response to decreasing dietary CP content meanwhile only ham intermuscular fat content increased with feeding level (P &lt;0·001). Thus, decreasing dietary protein concentration from well in excess of requirements and increasing energy intake enhance N and fat retention in the carcass but also increases intermuscular fat content in the ham of the Iberian pig with possible implications for meat quality.

The effects of dietary protein level during food restriction on carcass and non-carcass components, digestibility and subsequent compensatory growth in lambs

AbstractThe effect of proportion of dietary rumen non-degradable protein during food restriction on the weight of components of the digestive tract, carcass and subsequent growth was investigated in 37 Scottish Blackface wether lambs (initial live weight, 25 kg). Lambs were given individually ad libitum for 4 weeks a complete pelleted diet containing 150 g/kg white fish-meal (HP, 10·4 MJ metabolizable energy (ME) per kg dry matter (DM), 195 g crude protein (CP) per kg DM). Seven lambs were then slaughtered and 15 were switched to a diet containing no white fish-meal (LP, 10·4 MJ ME per kg DM, 122 g CP per kg DM) offered at 18 g DM per kg M per day, i.e. sufficient to maintain constant live weight. A further 15 continued to receive the HP diet at the same rate as the lambs given LP. After 6 and 12 weeks, five lambs on each diet were slaughtered. At 12 weeks the remainder received the HP diet ad libitum for a further 7 weeks before slaughter. During food restriction on both diets, the proportion of live weight formed by the carcass, the dissected components and the chemical composition remained the same as in the initial slaughter group. The relative weight of the non-carcass components fell during food restriction on both diets. There was a significant (P &lt; 0·05) interaction between slaughter date and dietary treatment for reticulo-rumen weight as a proportion of empty body weight (EBM); it was smaller in lambs on the HP diet after 12 weeks of restriction (HP: 0·022, LP: 0·026). A similar pattern was observed for the small intestine and the total digestive tract. During the 7 weeks of realimentation, lambs previously on HP and LP diets had similar intakes (1343 and 1208 g DM per day) and digestive tract components, body components and chemical composition of carcass and non-carcass components were all unaffected by previous treatment. The apparent digestibility of CP of the HP diet was greater than that of the LP diet although it was overall less degradable in the rumen. When both groups of lambs were realimented on the HP diet, there were no differences in the apparent digestibility of any of the dietary components. A high dietary protein: energy ratio during restriction reduced the weight of some of the components of the digestive tract but did not significantly affect carcass composition. The effect did not persist following realimentation and did not significantly influence subsequent performance.

The effect of cimaterol and oestradiol-17β alone or combined on growth and body composition of wether lambs

ABSTRACTTwenty-four Finn ♂ × Dorset Down ♀ wether lambs about 10 weeks and weighing on average 18 kg were allocated to treatment groups as follows: untreated controls (U); 15 mg oestradiol-17β (OE) implanted subcutaneously (O); cimaterol (2 mg/kg dry matter (DM)) in the diet (C); and 15 mg OE implant + cimaterol (2 mg/kg DM in the diet) (OC). The lambs were offered a diet, restricted to 38 g/kg live weight (LW), and which contained an estimated 12·5 MJ metabolizable energy and 137 g crude protein per kg DM for the experimental period of 62 or 63 days. Comparisons were made for the main effects of OE and cimaterol and also interactions between OE and cimaterol. Treatment with OE, on average, resulted in greater LW gain, DM intake, empty body weight (EBW), body length and chest depth, weight of shoulder and loin joints and carcass crude protein, but had no effect on fat deposition in carcass or depots. As a proportion of EBW, the weights of the pituitary gland and accessory vesicular glands were increased, as was teat length in lambs treated with OE. Cimaterol treatment, on average, increased LW gain, EBW, killing-out ratio, carcass weight and its weight of crude protein and, unlike OE, decreased the weight of the pituitary gland as a proportion of EBW and reduced the weight and proportion of fat in the carcass and perirenal and retroperitoneal depots. Increases in the cross-sectional area of m. longissimus dorsi and in the weight of selected major and minor commercial joints were also obtained in cimaterol-treated lambs. The presence of significant interactions indicated that there was incomplete or no additivity between the effects of cimaterol and OE for LW gain, cross-sectional area of m. longissimus dorsi and weights of carcass and carcass crude protein, omental fat and of certain of the dissected joints. These results suggest either that the mechanisms of action of oestradiol-17β and cimaterol are not independent or that they are affected by similar metabolic or physiological processes which limit the ability of castrated male sheep to exhibit a positive response.

The effect of dietary protein:energy ratio during food restriction on the size of the digestive tract and subsequent growth of lambs

During both food restriction and subsequent re-alimentation of sheep, the proportion of empty body weight formed by the gastro-intestinal components has been shown to change (Winter, Tulloh and Murray, 1976; Murray and Slezacek, 1988). The extent and nature of compensatory growth depends on the composition of the diet during restriction (Wilson and Osbourn, 1960). This study investigates the effect of rumen undegradable protein in the diet, during food restriction, on these processes. The hypotheses tested were that the protein:energy ratio of the diet during restriction to constant liveweight (LW) influences the relative proportions of the components of the digestive tract and its overall size as a proportion of empty body weight (EBW) a) during restriction and b) during subsequent growth on realimentation.

EMPTY BODY WEIGHTS, CARCASS WEIGHTS AND OFFAL PROPORTIONS IN BULLS AND STEERS OF DIFFERENT MATURE SIZE

Empty body weights, carcass weights and offal proportions were compared in 33 young beef bulls and 33 beef steers of different mature body size (35 small or mainly British breed crosses, 31 large or Continental crosses). All cattle were fed a high energy diet based on corn silage and high moisture corn from weaning to slaughter. Slaughter was carried out once 6 mm of fat had been attained at the 11/12th ribs, determined ultrasonically. Feed was removed 24 h and water 16 h prior to slaughter. The offal components were all weighed fresh and the alimentary components emptied of digesta. Bulls weighed 8.0% heavier (P &lt; 0.05) than steers at slaughter, while large animals were 38.7% heavier (P &lt; 0.0001) than small animals. Bulls and large animals had carcasses that dressed out 1.5% heavier than steers and small animals. To eliminate the effect of gutfill, carcass weights and offal components were expressed as a proportion of empty body weight. Bulls had a higher proportion of warm carcass weight and lower proportions of liver, spleen, heart, lungs, rumen, abomasum, large intestine and front feet relative to empty body weight than steers. Large animals had a greater proportion of warm carcass weight and hind feet, and a lower proportion of head, hide, liver, kidneys, omasum and small intestine relative to empty body weight than small animals. All castration by size interactions for liveweight, carcass weight, empty body weight and offal proportions were not significant. Castration and small animal size both increased the proportion of noncarcass parts relative to empty body weight in animals slaughtered at similar finish. Key words: Body, carcass, offal, bull, steer, maturity

Additive, nonadditive and maternal genetic effects on adiposity in mice fed different levels of fat.

Polygenic obese (M16), nonobese (ICR) and reciprocal crossbred (M16 male x ICR female and ICR male x M16 female) mice were fed ad libitum diets containing 1, 5 or 25% fat from 3 to 10 weeks of age. Epididymal and subcutaneous fat depot weights (E, S) and depot weights as a proportion of empty body weight (E%, S%) were used as measures of adiposity at 6 and 10 weeks of age. Genetic differences in adiposity among the four populations were partitioned into average direct (a), average maternal (m) and direct heterotic (h) effects. Line M16 was greater than ICR at both 6 and 10 weeks in E (81% at 6 weeks and 114% at 10 weeks), S (82%, 73%), E% (27%, 37%) and S% (26%, 12%). Average direct genetic effects, as determined by a, accounted for 60% of the M16 vs. ICR line difference in E and S at six weeks, the remainder of the difference being due to m. The major portion of the line difference in E% and S% at 6 weeks was accounted for by m. At ten weeks of age, most of the line difference in E, S, E% and S% was due to additive direct genetic effects while the contribution of maternal genetic effects was negligible. Heterosis was sizeable for all measures of adiposity, varying from 10.8% in S% at 10 weeks to 26.8% in E at six weeks, possibly indicating the presence of directional dominance. E and E% increased significantly with the increase in dietary fat percent, but S and S% were not affected. Interactions of genotype with level of dietary fat percent were not significant for the epididymal or subcutaneous fat depot weights or proportional weights.

The effect of compensatory growth in sheep on empty body weight, carcass weight and the weights of some offals

SummaryThe effects on the body composition of Corriedale wethers of weight loss, compensatory gain and constant body weight are described. Three groups of sheep were grown from 35–63 kg by different paths. The first grew continuously (fedad libitum). The second and third groups lost 20% and 28% of body weight (restricted intake), respectively, from 48 kg and were then fedad libitumuntil they reached 63 kg. Pairs of animals were slaughtered at intervals in each group. A fourth group of sheep was maintained at 48 kg. Analyses of covariance comparing regression equations were used to determine differences in body composition between the first three groups.The compensatory growth rates of both groups which had lost weight were 1·5–2 times those during continuous growth. These increases were associated with an increased gut content of these animals and a concomitant reduction in the proportion of empty body weight (EBW) and carcass weight (CW) in t he full body weight (FBW). Thus, the apparent dressing percentage (CW/FBW x 100) was reduced by 2% during compensatory growth. The carcass length was not reduced during weight loss and its growth in relation to the CW was not affected by treatment. Thus compensatory growth animals had longer carcasses. Similar increases in gut contents and carcass length were found for animals maintained at constant body weight.During developmental growth the proportions of the external offals, organs and gut tissue decreased in relation to the EBW; notable exceptions were the large intestine and caul fat where the proportions remained constant and increased, respectively.The growth of the CW, lungs, large intestine and head were not reversed during weight loss whilst the liver, heart, hide and gut tissues (except the large intestine) all lost more weight during weight loss than they had gained during the growth phase. The proportions of these latter components were increased in relation to the EBW during the ensuing compensatory growth.In general, the composition of animals held at constant body weight was similar to that of animals experiencing compensatory growth at the same weight and age.

Effects of three different growth rates on empty body weight, carcass weight and dissected carcass composition of cattle

SUMMARYA study was made of the effect on body composition of growing Angus steers from 300 to 440 kg at three different rates. The rates were: High (H) 0·8 kg/day, Low (L) 0·4 kg/day and High-Maintenance (HM) 0·8 kg/day followed by a period during which body weight was maintained constant.The animals were individually penned and the different growth rates were achieved by controlling intakes of a pelleted feed. Two animals (part of H treatment) were killed at 300 kg and the remaining 27 animals (nine in each treatment), were killed at common body weights of 330, 363, 400 and 440 kg.Analyses of covariance were used to compare linear regression equations representing results from each treatment. In order to do this, the logarithmic transformation of the allometric equation, y = axb, was used. As a proportion of empty body weight (EBW), hot carcass weight (HCW) was greater in both the HM and L groups than in the H group, indicating a greater offal component of EBW in the H animals. The loss in weight of the dressed carcass during storage at 2 °C for 24 h was similar in all three groups and was 0·98% of HCW. The proportions of HCW in the fore- and hind-quarters were similar in each group.At the same dissected side weight (DSW), the weight of bone was significantly greater in both the HM and L groups than in the H group indicating that bone development was related to both age and carcass weight. There were no significant differences between the groups in the proportions of either muscle or total fat. However, the proportion of kidney and channel fat in the H group was greater than in the HM and L groups and the proportion of subcutaneous fat was also greater in the H than in the L group. The amount of connective tissue in the three groups followed, in general, group differences in bone. Analyses of the dissected components of the separate fore- and hind-quarters showed that the difference between the H and L groups in the proportion of subcutaneous fat in the DSW was due to a relatively greater development of this fat in the fore-quarter of the H animals.No differences were found between treatments in the proportion of ‘expensive muscles’ relative to total side muscle (TSM). However, there were treatment effects on the proportions of TSM formed by certain groups of muscles; two examples are: the proportion of group 4 muscles (abdominal muscles) was higher and the proportion of group 6 muscles (distal muscles of the fore-leg) was lower in the H than in the L treatments. Bone weight distribution was similar in all treatments.There were differences between the H and HM groups in the relative growth ratios for all fat tissues (subcutaneous, intermuscular and kidney and channel fat) compared with total side fat. However, in the H and L groups, the relative growth ratios for corresponding fat categories were similar. The weight of kidney and channel fat in the left side of the carcass was significantly greater than in the right side of the carcass in all treatments.

Developmental growth and body weight loss of cattle. I. Experimental design, body weight growth, and the effects of developmental growth and body weight loss on the dressed carcass and the offal

At the age of approximately 11 months, 19 Angus steers were allotted to two experimental groups, namely, 10 to group A and 9 to group B. Group A animals were grown in pens and fed ad libitum. They were killed, two at each of the following of body weights: 250, 281, 316, 356, 400 kg. Group B animals were grown under similar conditions and killed at the same body weights as corresponding animals in group A; however, they were grown to weights 15% above their killing weights (growing-on phase) and then made to lose weight at 0.5 kg per day by restricting food intake until they reached their planned killing weights (weight loss phase). Huxley's (1932) allometric equation was used in logarithmic form as the basis for covariance analyses of the data. Empty body weight (EBW) increased as a proportion of full body weight as full body weight increased. EBW was higher in group A animals than in group B animals at the same full body weight, reflecting differences in weight of contents of the digestive tract. Dressed carcass weight increased as a proportion of EBW as EBW increased. Dressed carcass weight was higher in group B animals than in group A animals at the same EBW, indicating that the increase in carcass weight that occurred during the growing-on phase was not completely lost during the weight loss phase. During developmental growth, the weights of hide, feet, head, liver, gall bladder, heart, lungs, kidneys, and gut tissue decreased as proportions of EBW. The weight of abdominal fat increased as a proportion of EBW, while the weights of tail, spleen, and blood did not change significantly as proportions of EBW. During body weight loss, the weights of the feet, head, and tail remained close to the weights they had reached at the end of the growing-on phase, although, with the head, this varied considerably with the size of the animal before undergoing body weight loss. All other components lost weight during the weight loss phase. The hide, heart, lungs, and abdominal fat all reversed, approximately, the pattern of development that occurred during body weight growth. The liver, gall bladder, kidneys, gut tissue, spleen, blood, and thymus gland all lost more weight during the weight loss phase than they put on during the growing-on phase. With the liver, kidneys, and gut tissue, the proportion of weight lost varied according to the size of the animal before undergoing body weight loss.