Carcass Weight Fat Research Articles

Economic values for changes in carcass lean and fat weights at a fixed age for terminal sire breeds of sheep in the UK

Economic values for increases in the weights of carcass lean and fat for crossbred lambs at a fixed age, under UK commercial conditions, were estimated using a bio-economic model. Based around a biological model describing growth in lean and fat tissues over time, the model accounted for variation between lambs in rates of growth and fattening, seasonal fluctuations in market prices, feed requirements and seasonal variation in feed costs. Experimental data for female and castrated male Suffolk cross Mule lambs were used to adapt the model to represent typical commercial conditions. Lambs were sold for slaughter on reaching a chosen fatness level or when their carcass weight exceeded 21 kg. Carcass value was determined from its weight, fatness and conformation. Weekly market prices from six consecutive years were used in turn to investigate the effect of differences in prices between years. The economic values, calculated by comparing profit per animal before and after genetic increases in each trait, varied between sexes and among years. Economic values for lean weight ranged from 1.04 to 1.91£ kg −1 for females and from 1.16 to 1.93£ kg −1 for castrates. Values for fat weight ranged from −0.04 to −1.81£ kg −1 for females and from 0.69 to −2.60£ kg −1 for castrates. These values are specific to the breed-cross and production system considered. However, the model could be adapted to estimate economic values under other drafting strategies, or with appropriate data, other production systems and other breed-crosses of lambs.

Growth and carcass composition of tropical fat-tailed Menz and Horro sheep breeds

AbstractThe pattern of growth and carcass composition of indigenous Ethiopian fat-tailed Menz and Horro lambs were assessed through serial slaughter and carcass dissection of 147 lambs at five different growth phases. The GLM procedure of Statistical Analysis Systems Institute and allometric growth equations were used to assess the effects of various factors and differential growth of carcass components, respectively. Results showed that the growth and carcass composition of Menz and Horro lambs was significantly (P < 0.05 to P < 0.001) affected by the genotype, growth phase and season of birth of lambs. The effects of growth phase clearly showed that slower growth of the body and of carcass components was observed during the third phase (i.e. after weaning). Although there was an effect on fat to lean ratios (P < 0.05), growth phase had no significant effect on dressing out proportion, and lean to bone ratios. A significant influence of genotype (P < 0.001) and sex (P < 0.05) on lean to bone ratios indicated that the Horro sheep and ram lambs had a much more developed and heavier skeleton than the Menz sheep and ewe lambs. Higher pre-slaughter, hot carcass, lean and bone and fat weights of May/June born lambs revealed significant advantages of wet season lambing for fast growth and improved carcass composition. The log/log regression of weights of dissectible carcass components on hot carcass and empty body weight showed that the differential growth of bone was declining and that of lean was isometric relative to the growth of empty body weight. For carcass fat, the allometric growth coefficients (b) of 1.5 and 1.8 for Menz and Horro sheep, respectively indicated that fat is a late maturing body component. Moreover the growth of carcass fat relative to empty body weight in the Menz and Horro sheep is slower than that reported for tropical sheep breeds.

Carnitine Supplementation Fails to Maximize Fat Mass Loss Induced by Endurance Training in Rats

Background/Aims: Carnitine is a co-factor of the enzymatic system involved in long chain fatty acid transport across the mitochondrial membrane. This physiological role of carnitine raised the hypothesis that this compound could act as a ‘fat burner’ by optimizing fat oxidation and consequently reducing its availability for storage. Our aim was to verify whether carnitine supplementation could maximize fat mass loss in trained rats. Methods: Male Wistar rats (200 g) were divided into four groups: control (C), sedentary supplemented (S), trained (T) and trained supplemented (TS). The training protocol consisted of bouts of swimming exercise (60 min·day^–1) for 6 weeks. During the last 14 days, before sacrifice, the supplemented groups received a daily dose of 28 mg· kg^–1 of L-carnitine. Carcass fat content, weight and fat content of adipose tissues were evaluated in all experimental groups. Results: Our results indicate that carnitine feeding, per se, failed to promote fat mass loss. Endurance training successfully induced a decrease in the fat content in the carcass (28%) and the weight of adipose tissues (retroperitoneal and mesenteric depots by 41 and 20%, respectively) in comparison to C. Despite the augmented carnitine content in the soleus mitochondria (2-fold) observed in TS, the higher content did not maximize the fat loss induced by endurance training. Conclusions: Our data strongly suggest that endurance training, rather than carnitine content, is the major factor involved in fat mass loss.

Effects of dietary cis 9, trans 11-18:2, trans 10, cis 12-18:2, or vaccenic acid (trans 11-18:1) during lactation on body composition, tissue fatty acid profiles, and litter growth in mice.

Cis 9, trans 11 (c 9, t11)-18:2 and trans 10, cis 12 (t10, c12)-18:2 are the major conjugated linoleic acid (CLA) isomers in dietary supplements which reduce milk fat content in nursing women. The present study evaluated the effects of each CLA isomer or vaccenic acid on body composition and tissue fatty acids during lactation in mice. Dams were fed 30 g rapeseed oil (control)/kg diet or 20 g control plus 10 g 18:0, trans 11-18:1 (t11-18:1), c 9, t11-18:2, or t10, c12-18:2. Dietary t10, c12-18:2 reduced food intake by 18 % and carcass fat weight of the dams by 49 % compared with the other treatments. Milk fat percentage ranked by treatment was 18:0>t11-18:1=c 9, t11-18:2>t10, c12-18:2. The sum of saturated 12:0 to 16:0 in milk fat was lower when c 9, t11-18:2 was fed compared with the control, 18:0, or t11-18:1 treatments. Dietary t10, c12-18:2 caused further reductions in milk fat 12:0 to 16:0. The proportion of CLA isomers was 3-fold greater in milk fat than in the carcasses of the dams. The pups nursing from the dams fed t10, c12-18:2 had the lowest body weights and carcass fat, protein, and ash contents. Nursing from the dams fed c 9, t11-18:2 also resulted in lower carcass fat compared with the 18:0 or t11-18:1 treatments. The ratios of cis 9-16:1:16:0 or cis 9-18:1:18:0, proxies for Delta(9)-desaturase activity, were markedly lower in the carcasses of the dams and pups fed t10, c12-18:2. The ratio of 20:4n-6:18 : 2n-6, a proxy for Delta(6)- and Delta(5)-desaturase and elongase activity, in the liver of the dams and pups fed t10, c12-18:2 also was lower. Dietary t11-18:1 enhanced the content of c 9, t11-18:2 in milk fat and carcasses. As in previous studies, the reduction in food intake by t10, c12-18:2 could not entirely account for the marked decrease in carcass fat content and milk fat concentration. T10, c12-18:2 probably had a negative effect on Delta(9)-desaturase and mammary de novo fatty acid synthesis. Although these effects need to be confirmed in lactating women, the results suggest that the consumption of supplements containing t10, c12-18:2 should be avoided during the nursing period.

Effects of feeding intensity and time on feed on performance, carcass characteristics and meat quality of Simmental bulls

Seventy two Simmental bulls, weighing 489 kg and approximately 15 months old fed extensively or intensively on maize silage and concentrate mixture for 100 or 138 days, were divided into four groups to assess the effect of time on feed and feeding intensity on the performance, carcass and meat quality traits. Bulls intensively fed for 138 days before slaughter had higher final body weight (673.7 kg) compared with the other three groups (610.6 kg, as overall mean). Intensive feeding significantly increased the average daily gain (1371 g/day) and improved the feed efficiency (6.95 kg DM/kg gain) compared with extensive feeding (943 g/day and 7.97 kg DM/kg gain). No significant differences were detected by time on feed. Hot carcass and kidney fat weights were significantly higher for intensively fed bulls compared with extensive ones. Dressing percentage significantly increased for 138 day groups compared with 100 day groups. Carcass conformation and fatness scores significantly improved by intensive feeding. L and b * values were not affected by time on feed or feeding intensity. Slaughtering after 138 days on feed significantly elevated the meat redness value ( a *). Intensive feeding significantly decreased moisture and increased fat content of the longissimus dorsi muscle. Shear force, collagen content, juiciness, flavour and sarcomere length did not differ by time on feed or feeding intensity, while inconsistent effects were observed on tenderness and solubility of collagen.

Patterns of growth and partitioning of fat depots in tropical fat-tailed Menz and Horro sheep breeds

A total of 147 Menz and Horro lambs of both sexes were serially slaughtered and dissected at five different stages of growth to define the pattern of growth and partitioning of fat among body depots in indigenous Ethiopian Menz and Horro sheep breeds. The GLM procedure of SAS and allometric growth equation were used to assess the effects of various factors on the growth of body depots and to estimate its growth relative to total carcass fat (TCF) and empty body weight (EBW), respectively. Results obtained showed that the growth of carcass fat (CF), non-carcass fat (NCF) and tail fat (TF) is significantly affected by the genotype ( P<0.001) and stages of growth ( P<0.001) of lambs. Except for CF, the growth of both NCF and TF were also significantly affected ( P<0.001 and P<0.05) by the sex and the season in which the lambs were born. Of the two breeds, the Menz sheep deposited more fat into the carcass and less into the non-carcass depots as compared to the Horro sheep and ewe lambs in both breeds deposited more fat intra-abdominally than the ram lambs. The highest allometric growth coefficient was obtained for TF (1.2–2.1 relatively to TCF and EBW) and the lowest for NCF (0.8–1.3 relative to TCF and EBW) indicating that the former is a late developing while the later is an early maturing depot in the tropical fat-tailed Menz and Horro sheep breeds.

Consumo, Desempenho, Características de Carcaça e Biometria do Trato Gastrintestinal e dos Órgãos Internos de Novilhos Nelore Recebendo Dietas com Diferentes Níveis de Concentrado e Proteína

Foram utilizados 36 novilhos Nelore inteiros, com peso vivo inicial de 240 kg, distribuídos em oito tratamentos, com quatro diferentes níveis de concentrado nas dietas (20; 40; 60 e 80%) e dois níveis de proteína bruta (PB) (15 e 18%) e quatro animais referência.Foram determinados o desempenho, os rendimentos de carcaça, as porcentagens dos cortes básicos, o comprimento de carcaça, a área de olho de lombo, a espessura de gordura subcutânea, a porcentagem de músculo, gordura, osso, proteína, extrato etéreo e água da carcaça, os pesos dos órgãos e vísceras. O consumo de MS não foi influenciadopelo nível de concentrado, na fase de recria, apresentando média de 7,06 kg/dia, porém, quando foi expresso em porcentagem do peso vivo (% PV), estimaram-se consumos máximos de 2,59% PV com 42,60% de concentrado. Na fase de engorda, os níveis de concentrado não influenciaram o consumo de MS, observando-se valores médios de 7,16 kg/dia e 1,80% PV. O aumento do teor de proteína bruta da dieta, de 15 para 18%, aumentou o consumo de MS, na fase de recria, mas não influenciou o consumo na fase de engorda. O GMD e a CA não foram influenciados pelos níveis de concentrado da dieta, independentemente da fase estudada. A dieta com 18% de PB propiciou, aos novilhos, 22 e 22,6% a mais de ganho de peso na recria e na engorda, respectivamente, comparada à dieta com 15% de PB. Na fase de recria, os níveis de concentrado da dieta não influenciaram os rendimentos de carcaça; na fase de engorda, o aumento da inclusão de concentrado na dieta aumentou linearmente o rendimento de carcaça em relação ao PV. Não foi verificado efeito dos níveis de concentrado e dos teores de PB da dieta sobre os cortes básicos estudados, nas fases de recria e de engorda. Os níveis de concentrado da dieta apresentaram tendências de aumento da porcentagem de músculo e de diminuição da porcentagem de gordura na carcaça. Na engorda, o maior teor de PB propiciou carcaça com maior porcentagem de músculo e menor porcentagem de gordura. Na fase de recria, os pesos dos rins, baço, pulmões, fígado e os constituintes do trato gastrintestinal não foram influenciados pelos níveis de concentrado e nem pelos teores de PB da dieta. Na engorda, os níveis de concentrado não influenciaram o peso dos órgãos e os teores de PB influenciaram positivamente os pesos dos rins, pulmões e fígado. Os pesos relativos do rúmen+retículo, estômagos e trato gastrintestinal apresentaram comportamento linear decrescente com o aumento dos níveis de concentrado. Os teores de PB não influenciaram os pesos dos constituintes do trato gastrintestinal em nenhuma das formas expressas, em ambas as fases estudadas.

Responses to selection for lean growth in sheep

AbstractThis paper reports the selection responses achieved, and related results, following 9 years of index selection for lean growth in Suffolk sheep. The breeding goal of the index used comprised carcass lean weight and carcass fat weight at a constant age, with relative economic values of + 3 and –1 per kg. The selection criteria were live weight (LWT), ultrasonic fat depth (UFD) and ultrasonic muscle depth (UMD) adjusted to a constant age of 150 days. By year 9, responses in LWT, UFD and UMD in both sexes, as judged by the divergence between selection and control line performance, amounted to 4·88 kg, -1·1 mm and 2·8 mm respectively; these responses are between 7 and 15% of the overall means of the traits concerned. Although selection was originally on index scores based on phenotypic records, the retrospective analyses reported here used the mixed model applications of residual maximum likelihood to estimate parameters and best linear unbiased prediction to predict breeding values. The statistical model comprised fixed effects plus random effects accounting for direct additive, maternal additive and temporary environmental variation. Estimated genetic trends obtained by regressing estimated breeding values on year of birth were similar to annual responses estimated by comparing selection and control line means. Estimates of direct heritabilities were 0·054, 0·177, 0·286, 0·561 and 0·410 for birth weight (BWT), weaning weight (WWT), LWT, UFD and UMD respectively. Corresponding estimates of maternal heritabilities were 0·287, 0·205, 0·160, 0·083 and 0·164. Phenotypic correlations between all pairs of traits were positive and usually moderately high. There were low negative direct additive correlations between BWT and WWT, and between BWT and LWT, but higher positive maternal additive correlations between all other pairs of weight traits.

Comparing Genotypes of Different Body Sizes for Growth-related Traits in Chickens. Live Weight and Growth Performance under Intensive and Feed-restricted Extensive Systems

Three chicken breeds, including one commercial broiler (CB) and others from the Norwegian gene bank (Barred Plymouth Rock and Jaerhøn) differing in body size were raised under intensive ( ad libitum feeding) and extensive (restricted feeding) systems from 7 to 20 weeks. Body weight (every fortnight), carcass, breast, thigh and abdominal fat weights were recorded. CB chickens had heavier live weights, grew more rapidly and had heavier carcass components at slaughter under intensive conditions, but lost more weight under extensive conditions than the other two breeds. Intensive birds showed a higher degree of maturity than extensively reared birds. Males expressed their growth capacity much less than females under extensive conditions. Size scaling narrowed the gap between the performance of CB chickens and other genotypes but the specific genetic effect still remained. Therefore, both genetic and underlying size differences should be considered in breed comparisons, particularly when chickens are subjected to different feeding regimens.

Predição de características quantitativas de carcaças de suínos pela técnica de ultra-sonografia em tempo real

Foram utilizadas 48 fêmeas suínas, para se determinar o rendimento de cortes comerciais, após abate e dissecação das carcaças dos animais aos 50, 60, 70, 80, 90, 100, 110 e 120 kg. Foram tomadas medidas ultra-sônicas in vivo para área de olho de lombo e espessura de toucinho. Os preditores utilizados para estimar o rendimento de carne magra foram espessura de toucinho e área de olho de lombo, além das medidas feitas nos diferentes cortes, como peso do corte do pernil, peso do músculo do pernil, peso do músculo da paleta, peso do músculo do carré, peso do músculo da copa, e assim por diante, além dos dados de peso de músculo da carcaça total, peso da gordura da carcaça total, peso de ossos da carcaça total e peso de pele da carcaça total. Foram desenvolvidas equações de predição por meio de regressão linear simples e múltipla, a partir dos dados da dissecação e das medidas in vivo da área de olho de lombo, feitas por ultra-sonografia em tempo real. As equações de predição para quantificar os principais componentes dos cortes suínos tiveram ótimo ajuste, com R² superiores a 0,84 para músculos e desvio-padrão residual de 0,62 a 0,94. A técnica de ultra-sonografia em tempo real apresenta alta correlação com as medidas tomadas nas carcaças dos suínos e, por isso, estima a quantidade de carne na carcaça e o rendimento dos cortes comerciais com grande precisão. Concluiu-se que a técnica de ultra-sonografia em tempo real é acurada para predizer as principais características das carcaças dos suínos medidas in vivo.

Effects of Reduced Levels of Dietary Protein and Menhaden Fish Meal on Production, Dressout, and Biochemical Composition of Phase III Sunshine Bass Morone chrysops ♀× M. saxatilis ♂ Cultured in Earthen Ponds1

AbstractThe responses of phase III sunshine bass Morone chrysops ♀× M. saxatilis ♂ to diets containing reduced levels of menhaden fish meal (30–10%, dry weight) and crude protein (40–36%, dry weight) were evaluated in two separate experiments. Reductions in fish meal were compensated by increase in dietary soybean meal, a meat and blood meal product, and additional amounts of a 1:1 catfish oil:menhaden oil mixture sprayed on as a top dressing. Fish were cultured in earthen ponds and fed commercially manufactured, extruded diets to apparent satiation. In Experiment 1, dietary crude protein was reduced from 40 to 36% and the menhaden fish meal ingredient was reduced from 30 to 15% (dry weight). The mean weight of fish stocked into each pond ranged from 144 to 188 g, the stocking density was 8641/ha, and the duration of the growout was 172 d. In Experiment 2, both dietary treatments contained 40% crude protein (dry weight) and either 30% or 10% menhaden fish meal. The mean weight of fish stocked into each pond ranged from 42 and 77 g, the stocking density was 8,500/ha, and the duration of the growout was 175 d. Simultaneous reductions in dietary menhaden fish meal and crude protein resulted in significant decreases in all production indices except survival and percent weight increase. Weights of filet, carcass, liver and intraperitoneal fat, expressed as a percent of total body weight, were not significantly different. A 66% reduction in dietary menhaden fish meal while the crude protein level was maintained at 40% did not significantly affect growth, production, and weights of filet, carcass, liver and intraperitoneal fat, expressed as a percent of total body weight, and represents a 6% decrease in the cost of feed. In both experiments, levels of protein, lipid, moisture, and ash of the whole body and the filet were not significantly different. Fatty acid composition of the filet and livers from fish fed the control and experimental diets in Experiment 2 were highly comparable. The comparable level of performance of fish fed diets believed to be deficient in HUFA suggests that the dietary levels reported to be required may not be totally applicable to diets formulated for pond culture.

The use of ultrasound measurement of perirenal fat thickness to estimate changes in body condition of young female rabbits

AbstractForty-two New-Zealand x Californian young female rabbits of 4·5 months of age were used to evaluate the use o f a computerized ultrasound system in estimating changes in body condition. In order to get a wide range of fatness, animals were randomly subjected to four food restriction regimes for 2 weeks. Female rabbits were scanned at six different back sites to estimate perirenal fat thickness, using a real-time ultrasound unit equipped with a 5·0-MHz sector probe. After scanning, all animals were weighed and slaughtered. The weights of hot carcass, cold carcass, perirenal fat, scapular fat, liver and kidneys were recorded. There was a large variation in the weight of the main fat deposits, especially for the perirenal fat (CV = 0·632), indicating its suitability for estimating changes in body condition. Ultrasound measurements of perirenal fat thickness correlated strongly with all carcass fat weight values (r= 0·692 to 0·959;P&lt; 0·001) and the estimated carcass energy content (r= 0·777 to 0·866;P&lt; 0·001) and seem to be more precise predictors than live weight measurements. Multiple regression equations for estimating the main fat deposit weight and estimated carcass energy content using only the live weight as an independent variable hadR2values ranging from 0·47 to 0·59. The accuracy of estimates was improved when ultrasound measurements were used in the regression model (R2values ranging from 0·81 to 0·95). Ultrasound measurement of mean perirenal fat deposit thickness at 3 cm ahead of the 2ndto 3rdlumbar vertebrae was the best predictor for perirenal fat weight (R2= 0·95;P&lt; 0·001), total fat weight (R2= 0·93;P&lt; 0·001) and estimated carcass energy content (R2= 0·90;P&lt; 0·001). A validation group of 11 rabbit does was used to validate the ultrasound regression equations, showing that their mean accuracy was approximately 0·895 and 0·967 for total fat weight and estimated carcass energy content, respectively. Results suggest that ultrasound measurements of perirenal fat thickness may be an accurate method for studying changes in body condition of young female rabbits at different times.

Utilisation of two varieties of full-fat and simulated soyabeans in meal and pelleted diets by broiler chickens

Full-fat soyabeans (FFSB) (Glycine max) of two varieties, TGX 1440/E and M-351, and recombined soyabean meal and oil (SBMO, simulated soyabeans) along with a basal diet were evaluated in a growth and digestibility study designed to examine energy and nutrient digestibility and growth performance of broiler chickens fed the soyabean diets presented as meal or pellets. The soyabean products were incorporated into the basal diet in a 40:60 ratio (product/basal). The resulting eight experimental diets were assessed in a growth trial covering the starter to the finisher phase (1–8 weeks) of the broiler rearing period, during which daily weight gain, feed consumption and feed conversion efficiency were measured. Two digestibility trials were conducted at the starter (1.5–2 weeks) and finisher (7.5–8 weeks) phases of the broiler rearing. Apparent metabolisable energy (AME) and apparent fat (AFD), nitrogen (AND) and dry matter (ADD) digestibilities of diets were determined. Data on carcass and gut measurements were also obtained. The bird rearing phase had a significant (P ≤ 0.001) effect on energy and nutrient digestibility of diets and soyabean products, with the finisher broilers yielding higher values. Mean AME values for FFSB were 16.1 vs 13.6 MJ kg−1 DM for the finisher and starter broilers. Pelleting of diets improved AFD (P ≤ 0.001) and AME (P ≤ 0.10). Significant interaction (P ≤ 0.01) between diet and feed form resulted in improvement in fat digestibility of pelleted FFSB diets but not that of SBMO diets. Carcass fat (P ≤ 0.01) and breast weight (P ≤ 0.05) were increased and gizzard weight decreased (P ≤ 0.01) in birds given the pelleted diets compared with those on meal diets. Birds fed the TGX FFSB diets had significantly lower dietary fat and nitrogen digestibilities and heavier weight of the small intestine than those on the M-351 diets, thus suggesting varietal differences in the structure and nutritional value of soyabeans. © 2000 Society of Chemical Industry

Níveis de energia metabolizável para frangos de corte de 1 a 21 dias de idade mantidos em ambiente de conforto térmico

Este experimento foi realizado para avaliar níveis de energia metabolizável (EM) (2850, 2921, 3000, 3075 e 3150 kcal/kg) para pintos de corte, machos, de 1 a 21 dias de idade, mantidos em ambiente de conforto térmico. Quatrocentos e cinqüenta pintos, machos, com 44±0,2 g de peso inicial médio, foram distribuídos em delineamento experimental inteiramente casualizado, com cinco tratamentos, nove repetições e dez aves por unidade experimental. O nível de EM da ração influenciou o ganho de peso médio diário e o consumo de energia metabolizável, que aumentaram, e a conversão alimentar, que reduziu linearmente com o aumento do nível de energia da ração. O nível de EM da ração influenciou as taxas de deposições de proteína e gordura na carcaça e o peso de gordura abdominal, que aumentaram linearmente, enquanto o rendimento de carcaça não foi influenciado. O nível de 3075 kcal EM na ração proporcionou o melhor desempenho das aves mantidas em condição de conforto térmico, na fase de 1 a 21 dias de idade.

Addition of fat to the diets of lactating sows: I. Effects on milk production and composition and carcass composition of the litter at weaning.

In Exp. 1 two groups of 18 sows were used to evaluate the effects of supplemental dietary fat on sow and litter performance and milk production and composition. Sows were provided ad libitum access to either a corn-soybean meal (control) diet or a similar diet containing 10% tallow. Feed intake, ME intake, and milk yield did not differ (P > .10) between treatments. The percentage of solids in milk was greater (P < .05) for sows fed the tallow diet, due to an increase (P < .05) in the fat and ash content. Compared with percentages of fatty acids in milk of sows fed the control diet, the percentages of C10:0, C14:0, C16:0, C16:1, and C18:3 fatty acids were lower (P < .05) and the percentages of C18:0 and C18:1 fatty acids were higher in milk of sows fed tallow diets (P < .05). In Exp. 2, 30 sows were fed diets similar to those fed in Exp. 1, and the effects of a tallow diet on pig carcass composition at weaning were determined. Litter size was standardized to 10 pigs. There were no differences (P > .10) in ADFI of sows. Daily ME intake was greater for sows fed tallow than for control sows during wk 2 (P < .05), wk 3 (P < .10), and the entire lactation (P < .05) period. Litter weaning weight was greater (P < .05) for pigs from sows fed tallow diets than for pigs from control sows. Pigs from tallow-fed sows had greater carcass fat weight and fat percentages (P < .05) and lower water and protein percentages (P < .05). These data indicate that the increased fat content of milk from sows fed tallow diets resulted in an increased weight gain for litters nursing these sows. The composition of the increased weight gain is almost exclusively fat.

Effect of various dietary nutrient density on the growth performance of local male ducks and their crosse

Three hundred day-old male ducklings were allocated randomly into 12 treatment combinations in 3 x 4 factorial design . Three levels of dietary density ration i.e : Low(12% /2,000 kcal), medium (16%/2,500 kcal) and high (20%/3,000 kcal) and 2 breeds of local ducks Tegal (TT) and Mojosari (MM) and their crossbreds (Tegal x Mojosari (TM) and Mojosari x Tegal (MT)) were applied. Each treatment combination consisted of5 replicates, each of 5 birds. The experiment was carried out for 8 weeks and measurements were weekly feed intake, body weight, weight and/or percentage of carcass, internal organs and abdominal fat. Results indicated that no significant interaction was detected between dietary nutrient density and the breeds of ducks on all parameters measured . Breeds of duck, as well as their crosses did not affect growth performance and other parameters . On the other hand, nutrient density influenced growth performance significantly, except for percentage of carcass and internal organs . In general, feed intake, body weight gain, feed efficiency, carcass weight and abdominal fat of ducks fed low density ration were significantly lower than those fed medium density, which were also lower than those fed high nutrient density diet . Weghtand length of intestine and kidney weight, of ducks fed low density diet however, were higher than the two other treatments . Keywords : Dietary density ration, breeds of duck, growth

Effects of heat stress on growth, carcass traits and blood components of New Zealand White rabbits fed various dietary energy–fibre levels, under Egyptian conditions

Eighty weaned male New Zealand White rabbits were offered diets with normal or high energy (NE, HE) and normal or high fibre (NF, HF) contents, to appetite. Rabbits reared in summer showed a reduction in final body weight, daily weight gain, feed intake, final margin (financial return), weights of carcass and kidney fat and all blood components compared to those reared in winter. Rabbits fed HE diet showed significantly higher final body weight, daily weight gain, final margin and carcass weight than those fed NE diet, while feed intake decreased. The dietary energy level did not have any significant effect on blood components, except the serum albumin which increased with increasing dietary energy. The HF diet gave significantly higher values in carcass weight, kidney fat weight and creatinine, and significantly lower values in serum total protein, globulin and SGOT when compared to the LF diet. Interaction between season and dietary energy level showed highly significant effects on final body weight, daily weight gain and serum total protein. Interaction between season and dietary fibre level showed significant effects on final body weight, daily weight gain and kidney fat weight. The interactions between dietary energy and fibre levels or between season, dietary energy and dietary fibre did not show any significant effect on the studied traits. Rabbits fed HE-HF diet in winter recorded the highest values in most of the growth performance and carcass traits when compared with the other winter and summer groups. In summer, rabbits fed HE-NF diet showed better body gain than other summer rabbits.

Effects of age at photostimulation on reproductive efficiency and carcass characteristics. 2. Egg-type hens

Increasing day length is the primary cue for the timing of sexual maturation in poultry. Typically, Single Comb White Leghorn (SCWL) pullets are reared under conditions of short days (8L:16D) until 18 wk of age. In this study, the effects of varying the age at photostimulation from 16, 18 or 20 wk of age were studied in terms of carcass composition at photostimulation and at sexual maturity, as well as reproductive performance.A flock of 1600 SCWL pullets (Shaver 288 strain) were housed in floor pens in light-tight facilities (8L:16D). All birds were provided with ad-libitum access to both feed and water. At 16 wk, 18 wk and 20 wk, 50 birds per treatment were moved to laying cages and provided to a photoperiod of 14L: 10D. An additional 288 birds per treatment were housed two birds per cage, and group egg production and feed consumption data were collected to 64 wk of age. At photostimulation (n = 20 birds per treatment) and on the day following the first oviposition, (n = 20 birds per treatment) birds were killed by cervical dislocation. All surviving hens were killed at 64 wk of age. All carcasses were studied in terms of selected organ weights and reproductive organ morphology. Birds killed at photostimulation and at sexual maturity were further studied for whole body carcass composition.Significant differences were found in dry matter, water, lipid and ash content among treatment groups at the age of photostimulation. As age at photostimulation increased, absolute weight of carcass fat, protein and ash increased. The percent carcass lipid content increased for all groups between photostimulation and sexual maturity with the 16 wk treatment group showing the largest increase. The time required to reach sexual maturity from the age of photostimulation decreased as the age at photostimulation increased. No significant differences were found in total egg production. The 16 wk group laid significantly smaller eggs. Delaying sexual maturity until 20 wk of age resulted in an increased prime sequence length and fewer pause days to produce approximately the same number of eggs as birds that were photostimulated at 16 wk of age. Key words: Chicken, egg-type hens, sexual maturity, egg production, carcass composition

Prediction of carcass composition in the rabbit

Carcass composition of two synthetic rabbit breeds was predicted from retail cuts and external measurements by using regression equations. Breed R has a higher adult weight and reaches slaughter weight 1 week before breed V. Sixty rabbits of each breed were slaughtered when they (approximately) reached the Spanish commercial liveweight of 2kg. The carcasses were measured and retailed according to the norms of the World Rabbit Scientific Association. Rabbit carcass composition is well defined by meat percentage of the commercial carcass and ratio meat bone . External measurements on the carcass, retail cuts and meat of retail cuts or muscular masses are all bad predictors of carcass meat percentage or ratio meat bone ( R 2 < 0.53). The ratio meat bone of the hind leg can give reasonable predictions for carcass meat percentage and meat bone ratio ( R 2 = 0.60 and 0.69). Dissectible carcass fat weight and dissectible carcass fat percentage can be predicted by the perirenal fat weight ( R 2 = 0.77 and 0.69). Fat depots had a low predictive power for fat percentage of the dissected meat in the half carcass.

Growth and body composition of entire and castrated fallow bucks (Dama dama) treated with zeranol

AbstractA 2 × 2 factorial experimental design was used to compare growth in entire and castrated fallow bucks, implanted with zeranol at 6 and 9 months of age, or left as controls (no. = 10 per group). Growth pattern at pasture was assessed using 10-monthly growth periods from weaning (6 months) to 17 months. There were no overall castration or zeranol effects on growth rates from weaning to 17 months (P &gt; 0·05), although there were significant interactions of zeranol and castration with time (P &lt; 0·05). Zeranol-treated animals grew faster than the controls from 6 to 14 months, compared with the last 3 months (P &lt; 0·05), indicating that the zeranol implants given at 6 and 9 months of age were no longer effective over the last 3 months of the experiment. The interaction between castration and time was significant (P &lt; 0·05), whereby entire males grew relatively faster than the castrated males in both spring and the average of the winter and spring periods, whilst there was little difference in growth rates between entire and castrated males during the autumn period.At 17 months of age all animals were slaughtered following a 16-hfast. Entire bucks were 46g/kg live weight and 56 g/kg carcass weight heavier than the castrated bucks at slaughter (P &lt; 0·05), although there was no effect of zeranol treatment on either live or carcass weights (P &gt; 0·05). The mean dressing proportion for deer in all groups was 0·61.A subset of each treatment (no. = 5) were slaughtered and half carcasses dissected into muscle, bone and fat. When compared at the same carcass weight, both castration and treatment with zeranol significantly reduced the muscle weight and increased carcass fat weight (P &lt; 0·05). There was no effect of either castration or zeranol treatment on the distribution of primal cuts. There were significant castration × zeranol interactions (P &lt; 0·05) for muscle: bone and muscle: fat ratios, the entire control group having the highest muscle: bone and muscle: fat ratios.It was concluded that there is little commercial basis for the use of the growth promotant zeranol in fallow bucks being grown for venison. Although castration resulted in lower carcass weights and muscle proportion, these disadvantages should be considered against the management advantages of easier handling and lower bruising of castrates.