• Asian-Australasian Journal of Animal Sciences
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• v.18 no.8
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• pp.1075-1079
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• 2005

The main objective of this study is to examine genetic changes in growth rate and carcass composition traits in group housed, ad libitum fed pigs, from lines of Large White divergently selected over four years for high and low post-weaning daily gain on a fixed but restricted ration. Genetic parameters for production and carcass traits were also estimated by using average information-restricted maximum likelihood applied to a multivariate individual animal model. All analyses were carried out on 1,728 records of group housed ad libitum fed pigs, and include a full pedigree of 5,324 animals. Estimates of heritability (standard errors in parentheses) were 0.11 (0.04) for lifetime daily liveweight gain (LDG), 0.13 (0.04) for daily carcass weight gain (CDG) and 0.28 (0.06) for carcass backfat (CFT). Genetic correlations between LDG and CDG were highly positive and between LDG and CFT negative, suggesting that selection for lifetime daily gain under commercial conditions of group housing with ad libitum feeding would result in favourable improvement in carcass traits. CFT showed negative genetic correlations with CDG. Correlated genetic responses evaluated as estimated breeding values (EBVs) were obtained from a multivariate animal model-best linear unbiased prediction analysis. After four years of divergent selection for 6 week post-weaning growth rate on restricted feeding, pigs performance tested on ad libitum feeding in groups exhibited changes in EBVs of 6.77 and -9.93 (g/d) for LDG, 4.25 and -7.08 (g/d) for CDG, and -1.42 and 1.55 (mm) for CFT, in the high and low lines, respectively. It is concluded that selection for growth rate on restricted feeding would significantly improve genetic performance and carcass composition of their descendants when group housed and ad libitum fed as is a common commercial practice.

• Asian-Australasian Journal of Animal Sciences
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• v.32 no.2
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• pp.209-216
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• 2019

Objective: We compare the effects of three different approved sources of supplemental zilpaterol on growth-performance responses and carcass characteristics of finishing lambs. Methods: Twenty four Pelibuey${\times}$Katahdin lambs ($46.75{\pm}2.43kg$) were used in a 33-day feeding trial. Lambs were fed a dry rolled corn-based finishing diet. Treatments consisted of the non-supplemental basal diet (Control) versus the basal diet supplemented with 125 mg zilpaterol/kg of diet (as fed basis) from three commercial sources marketed in Mexico: Zilmax (ZIL), Grofactor, and Zipamix. Results: Compared to controls, zilpaterol (ZH) supplementation did not affect dry matter intake (DMI), but increased carcass adjusted daily weight gain (ADG, 36.7%), gain efficiency (34.2%), and dietary net energy (26.0%), and decreased (23.4%) the ratio of observed:expected DMI. Compared to controls, supplemental ZH increased hot carcass weight (6.4%), dressing percentage (3.2%), m. longissimus thoracis (LM) area (15.6%), and shoulder muscle:fat ratio (28.7%), but decreased kidney-pelvic-heart fat, and fat thickness. Supplemental ZH increased 10.9% and 14.3% whole cut weight of loin and leg, respectively, and the proportion (as percentage of cold carcass weight) of leg (4.3%). These increases were reflected in greater forequarter and hindquarter weights. Lambs fed ZH increased (4.6%) empty body weight (EBW) and reduced (14.7%) liver/spleen weight (as g/kg EBW). Likewise, ZH supplementation tended (p = 0.08) to lower (8.9%) visceral fat. Growth performance, energetic efficiency, hot carcass weight, dressing percentage, LM area and whole cuts were not different across supplemental ZH sources. However, compared with non-supplemented controls, only ZIL appreciably decreased carcass fat distribution, including fat thickness, percentage kidney pelvic and heart fat, shoulder fat, and visceral fat. Conclusion: Supplemental ZH increases ADG, gain efficiency, carcass dressing percentage, and LM area. The magnitude of these responses was similar among ZH sources. Nevertheless, compared with non-supplemented controls, only ZIL appreciably decreases carcass fat. The basis for this is uncertain, but indicative that some practical differences in zilpaterol bio-equivalency may exist across commercial sources tested.

• Asian-Australasian Journal of Animal Sciences
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• v.31 no.6
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• pp.859-863
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• 2018

Objective: Since very little information exists about the topic; in this experiment we compare, in a long-term finishing program, the growth-performance responses and carcass characteristics of Holstein steers where non-structural carbohydrate concentration of the diet is reduced from 64% to 51% (dry matter basis). Methods: Sixty Holstein steer calves ($129{\pm}2.2kg$) were blocked by initial weight into five groups and randomly assigned within weight groupings to 10 pens. Calves were fed with a steam-flaked corn-based finishing diets containing 51% higher fiber (HF) or 64% lower fiber (LF) nonstructural carbohydrates. Non-structural carbohydrates concentrations were manipulated substituting dried distiller grain with solubles and alfalfa hay for flaked corn. Cattle were weighed every 112 days and at the end of the experiment (day 308) when the cattle were harvested and carcass characteristics were evaluated. Results: Steers fed the HF diet showed improvement (8.8%) in average daily gain (ADG) during the initial 112-d period. This effect was followed by a numerical trend for greater ADG throughout the remainder of the study so that overall ADG tended to be greater (4.9%, p = 0.06) for the HF than for LF. There were no treatment effects on dry matter intake. Gain efficiency and estimated dietary net energy (NE) were greater 8.3% and 5.2%, respectively for HF during the initial 112-d period. Overall (308-d) gain efficiency and estimated dietary NE were similar for both dietary treatments. However, due to differences in tabular dietary NE, the ratio of observed:expected dietary NE tended to be greater (4.1%, p = 0.06) for the HF vs LF diet. There were no treatment effects on carcass characteristics except for a tendency toward a slightly greater (0.5%, p = 0.09) estimated carcass yield. Conclusion: Reducing the non-structural carbohydrate concentration of a conventional steam-flaked corn-based growing finishing diet for Holstein steers can effectively enhance growth performance, particularly during the early growing and late finishing phases.

• Asian-Australasian Journal of Animal Sciences
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• v.8 no.3
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• pp.223-229
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• 1995

The effects of palm oil and soybean oil as a high energy source diet on the performance of broilers under the warm humid environment were studied. Palm oil and soybean oil, either singly or mixed, were incorporated in the experimental diets to a total of 6% of the diet. The performance of the chicken improved (though not significant) with increasing unsaturated fatty acid content in the diets, but the responses to treatments were not consistent. The carcass fat content was generally higher in all the treated groups compared to the control but the differences were not statistically significant. The results also failed to show any effect of combining two sources of oils. Fatty acid composition in the body was found to be influenced greatly by dietary fat. When soybean oil was used instead of palm oil, the amount of linoleic and linolenic acids in the carcass were increased proportionately.

• Asian-Australasian Journal of Animal Sciences
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• v.26 no.5
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• pp.705-710
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• 2013

This study was conducted to determine the effects of three different fat sources and their combination on growth performance, carcass traits and intestinal measurements of broiler chickens reared to 42 d of age. Two hundred day-old male broiler chicks (Ross 308) were randomly assigned to one of five treatments with four replicates of 10 chicks based on a completely randomized design. The dietary treatments consisted of 4% added fat from three different sources and their combination as follows: T, diet containing 4% tallow; CO, diet containing 4% canola oil; SFO, diet containing 4% sunflower oil; TCO, diet containing 2% tallow+2% canola oil; TSFO, diet containing 2% tallow+2% sunflower oil. Dietary fat type affected significantly BW and gain as well as feed efficiency in birds fed the TCO diets compared with those fed the other diets. Dietary fat type also modified meat yield, resulting in a higher breast and drumstick yields in the birds fed TCO and TSFO diets, respectively. Most of internal organ relative weights and small intestine measurements were not influenced by dietary treatments, except for the abdominal fat pad weight that was lower in birds fed SFO and for small intestinal length that was influenced by fat source. Results from the current study suggested that the supplementation with a combination of vegetable and animal fat sources in broiler diet supported positively growth performance and carcass parameters.

• Asian-Australasian Journal of Animal Sciences
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• v.30 no.8
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• pp.1074-1080
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• 2017

Objective: The growth, carcass and retail cut yield records on 1,428 Hanwoo steers obtained through progeny testing were analyzed in this study, and their heritability and genetic relationships among the traits were estimated using animal models. Methods: Two different models were compared in this study. Each model was fitted for different fixed class effects, date of slaughter for carcass traits and batch of progeny test live measurement traits, and a choice of covariates (carcass weight in Model 1 or backfat thickness in Model 2) for carcass traits. Results: The differences in body composition among individuals were deemed being unaffected by their age at slaughter, except for carcass weight and backfat thickness. Heritability estimates of body size measurements were 0.21 to 0.36. Heritability estimates of retail cut percentage were high (0.56 from Model 1 and 0.47 from Model 2). And the heritability estimates for loin muscle percentage were 0.36 from Model 1 and 0.42 from Model 2, which were high enough to consider direct selection on carcass cutability traits as effective. The genetic correlations between body size measurements and retail cut ratio (RCR) were close to zero. But, some negative genetic correlations were found with chest girths measured at yearling (Model 1) or at 24 months of age or with chest widths. Loin muscle ratio (LMR) was genetically negatively correlated with body weights or body size measurements, in general in Model 1. These relationships were low close to zero but positive in Model 2. Phenotypic correlation between cutability traits (RCR, LMR) and live body size measurements were moderate and negative in Model 1 while those in Model 2 were all close to zero. Conclusion: Therefore, the body weights or linear body measurements at an earlier age may not be the most desirable selection traits for exploitation of correlated responses to improve loin muscle or lean meat yield.

• Korean Journal of Agricultural Science
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• v.49 no.3
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• pp.547-560
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• 2022

The present study investigated the effects of dietary supplementation of peanut shell extract on the growth performance and physiological properties of broiler chicks. Two diet energy levels (Positive and Negative) and four additives (0.0, 0.05, and 0.1% peanut shell extract and commercial antioxidant) were factorially arranged for eight treatments. The overall weight gain of the broilers was slightly improved at 0.05% for the antioxidant treatments regardless of the diet energy levels, but there was no statistical difference among the treatments (p > 0.05). The carcass characteristics of the broilers, such as cooking loss, crude protein content, antioxidant activity, and thiobarbituric acid reactive substances (TBARS) values, were improved by the feeding diets containing the 0.05% peanut shell extract. Furthermore, it was confirmed that the dietary supplementation of peanut shell extract did not have a negative effect on the immune responses of the broilers show by the lack of statistical differences in the liver and bursa Fabricious weight and cytokine level among the treatments. From the economic analysis, dietary supplementation of peanut shell extract significantly influenced the compensatory growth and food efficiency and, in turn, led to a decrease in the duration needed to reach 1.5 kg compared to the control. These results suggest the possibility that the peanut shell extract could be used as a functional feed additive by improving the growth performance and carcass characteristics with no detrimental effects on broilers.

• Asian-Australasian Journal of Animal Sciences
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• v.19 no.11
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• pp.1643-1648
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• 2006

To investigate the effects of feeding restricted on growth, carcass characteristics and plasma profiles in an attempt for optimum responses, a total of 108 cross-bred finishing barrows [(Landrace${\times}$Yorkshire)${\times}$Duroc]weighing an average of $46.88{\pm}0.52kg$ were assigned in a randomized complete block (RCB) design to one of four treatments with three replicates and nine pigs per pen. Feeding regimens were, 1) ad libitum from 50 kg to market weight (Ad 3/3), 2) restricted feeding from 90 kg to market weight (Ad 2/3), 3) restricted feeding from 70 kg to market weight (Ad 1/3), and 4) restricted feeding from 50 kg to market weight (Ad 0/3). During the experimental period, average daily feed intake (ADFI) was decreased from 2.53 kg (AD 3/3) to 2.09 kg (AD 0/3) with increasing restricted feeding duration of (p<0.05). Average daily gain (ADG) of AD 3/3 (0.79 kg) was significantly higher (p<0.05) than those of AD 1/3 (0.74 kg) or AD 0/3 (0.72 kg). Feed efficiency was not influenced by restriction regimens. Blood IGF-I concentrations were increased from 74.14 to 134.25 (167.36-115.66) ng/ml as body weight increased. Blood leptin concentrations were affected by feed intake level and coincided with blood IGF-I concentrations. Most of carcass characteristics were not significantly affected by restricted feeding, however cooking losses in AD 1/3 and Ad 0/3 treatment diet were higher than those in Ad 3/3 and Ad 2/3. In addition, there was a trend that backfat thickness was lowered in proportional to decreasing feed intake (p>0.05). In conclusion, restricted feeding improved feed efficiency after 50 kg body weight without deteriorating the pork quality of barrows.

• Asian-Australasian Journal of Animal Sciences
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• v.26 no.2
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• pp.247-252
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• 2013

An experiment was conducted to determine the effect of supplementing various concentrations (0, 100, 200, 300, or 400 ${\mu}g/kg$ diet) of organic Se on growth performance, carcass traits, oxidative stress, and immune responses in commercial broiler chickens reared in open-sided poultry house under tropical climatic conditions. Each diet was fed ad libitum to eight replicates consisting of six birds in each pen from 1 to 42 d of age. Body weight gain and feed efficiency, and relative weight of liver, abdominal fat and ready to cook yields were not affected (p>0.05) by organic Se supplementation to broiler diets. Lipid peroxidation in plasma decreased, while activities of glutathione peroxidase and glutathione reductase in plasma increased (p<0.01) linearly with Se concentration in diet. The ratios between heterophyls and lymphocytes and relative weight of lymphoid organs (bursa, spleen, and thymus), and antibody production to Newcastle disease vaccination were not affected (p>0.05) by Se supplementation to broiler diets. However, the cell-mediated immunity (lymphocyte proliferation ratio) increased (p<0.01) linearly with dietary Se concentration. The results of the present study indicate that the supplementation of Se did not influence body weight and feed efficiency. However, supplementation of Se increased antioxidant status and lymphocyte proliferation in broiler chickens.

• Asian-Australasian Journal of Animal Sciences
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• v.24 no.5
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• pp.662-669
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• 2011

An experiment was conducted with broiler (Cobb 400) male chicks (n = 480) to determine the effect of betaine (Bet) supplementation (0 and 800 mg/kg) to diets containing five concentrations (15, 18, 20, 22 and 24 g/kg crude protein, CP) of methionine (Met) in a $2{\times}5$ factorial study for performance, carcass traits, immune responses, and serum parameters. Each diet was fed ad libitum from 1 to 42 d of age to 8 replicates of 6 chicks. Birds were housed in battery brooders placed in an open-sided poultry shed. Body weight gain, feed intake, feed conversion efficiency and slaughter variables were recorded at 21 and 42 d of age. Serum biochemical profile, antibody production against Newcastle disease (ND) and lymphocyte proliferation ratio (LPR) were analysed at 42 d of age. Supplementing Bet to diets containing sub-optimal concentrations of Met (15 g/kg) improved weight gain and breast yield at 21 d of age (p<0.01), and feed conversion efficiency at 42 d of age (p<0.05). Feed efficiency at 21 d of age, body weight gain at 42 d of age, slaughter variables except breast yield at 21 d of age and ND antibody titres were not affected (p>0.05) by the interaction. LPR increased (p<0.05) with Bet supplementation at 20 g Met/kg CP equal to those broilers fed 24 g Met without Bet. Bet supplementation enhanced the concentrations of protein, globulin and cholesterol in serum of broilers fed sub-optimal concentrations of Met. Results suggested that Bet supplementation (800 mg/kg diet) enhanced growth (21 d), feed conversion efficiency (42 d), breast yield and lymphocyte proliferation in broilers fed a diet containing 15 g Met/kg CP.