scholarly journals Effects of zilpaterol hydrochloride and zinc methionine on growth performance and carcass characteristics of beef bulls

2015 ◽  
Vol 95 (4) ◽  
pp. 609-615 ◽  
Author(s):  
Miguel A. Rodríguez-Gaxiola ◽  
Ignacio A. Domínguez-Vara ◽  
Rubén Barajas-Cruz ◽  
María A. Mariezcurrema-Berasain ◽  
José L. Bórquez-Gastelum ◽  
...  
Keyword(s):  
Growth Performance ◽  
Crude Protein ◽  
Average Daily Gain ◽  
Carcass Characteristics ◽  
Backfat Thickness ◽  
Longissimus Dorsi ◽  
Carcass Yield ◽  
Zilpaterol Hydrochloride ◽  
Zinc Methionine ◽  
Beef Bulls

Rodríguez-Gaxiola, M. A., Domínguez-Vara, I. A., Barajas-Cruz, R., Mariezcurrema-Berasain, M. A., Bórquez-Gastelum, J. L. and Cervantes-Pacheco, B. J. 2015. Effects of zilpaterol hydrochloride and zinc methionine on growth performance and carcass characteristics of beef bulls. Can. J. Anim. Sci. 95: 609–615. Sixty beef bulls with a body weight (BW) of 314.7±16.2 kg were used to evaluate the effects of zilpaterol hydrochloride (ZH) and zinc methionine (ZM) on growth performance and carcass characteristics. The experimental design was a randomized complete block, with a factorial 2×2 arrangement of treatments (ZH: 0 and 0.15 mg kg−1 BW; ZM: 0 and 80 mg kg−1 dry matter). The ZH increased (P<0.05) the final BW, average daily gain, feed conversion, carcass yield and longissimus dorsi area. Bulls fed ZH plus ZM had less (P<0.01) backfat thickness and intramuscular fat (IMF) compared with those fed ZH or ZM alone. The ZH increased (P<0.02) the meat crude protein content and cooking loss. It is therefore concluded that ZH increases growth performance, carcass yield, longissimus dorsi area, and meat crude protein. The interaction of ZM and ZH did not present additional advantages. The reason for the reduction in backfat thickness and IMF by ZH plus ZM is unclear, and implies that our knowledge of β-agonistic adrenergic substances and their interactions with minerals is incomplete.

scholarly journals Effect of crude protein content and undegraded intake protein level on productivity, blood metabolites, carcass characteristics, and production economics of Hanwoo steers

2020 ◽  
Vol 33 (10) ◽  
pp. 1599-1609
Author(s):  
Youn Hee Lee ◽  
Farhad Ahmadi ◽  
Myun Lee ◽  
Young-Kyoon Oh ◽  
Wan Sup Kwak
Keyword(s):  
Growth Performance ◽  
Crude Protein ◽  
Average Daily Gain ◽  
Carcass Characteristics ◽  
Blood Cholesterol ◽  
Blood Metabolites ◽  
Carcass Quality ◽  
Production Economics ◽  
Muscle Area ◽  
Feeding Diets

Objective: This study was designed to determine how feeding diets differing in crude protein (CP) and undegraded intake protein (UIP) levels affected productivity, blood metabolites, carcass characteristics, and the production economics of Hanwoo steers.Methods: Thirty-six Hanwoo steers (age = 8.2±0.5 mo; body weight = 254±16.1 kg) were assigned at random to one of three treatments (4 steers/pen; 3 pens/treatment): i) a low-CP diet (LP; control) containing 12.1% CP with 35.1% UIP, 12.0% CP with 36.8% UIP, and 12.9% CP with 48.8% UIP, in the growing, fattening, and finishing periods, respectively; ii) a high-CP, low-UIP diet (HPLU) containing 15.0% CP with 33.7% UIP, 14.0% CP with 35.7% UIP, and 13.1% CP with 46.7% UIP, respectively; and iii) a high-CP, high-UIP diet (HPHU) containing 15.0% CP with 45.8% UIP, 14.0% CP with 44.6% UIP, and 13.0% CP with 51.1% UIP, respectively.Results: The treatments did not affect feed intake and growth performance, except for average daily gain during the fattening period that tended to be the lowest (p = 0.08) in the HPLUfed steers. The feed CP conversion ratio over the entire feeding period was higher with high-CP diets. The treatments did not affect most blood metabolites; however, blood cholesterol and low-density lipoprotein concentrations during the fattening and finishing periods were the lowest in steers fed a HPLU diet. The treatments had negligible effects on cold carcass weight, yield traits including longissimus muscle area, backfat thickness, yield index, and yield grade, plus quality traits including meat color, fat color, texture, and maturity. However, marbling score and frequency of carcass quality grade 1++ were greater in HPHU-fed steers.Conclusion: Feeding diets with higher CP and UIP levels did not affect growth performance but tended to improve the carcass quality of Hanwoo steers, resulting in greater economic return.

scholarly journals By-products of apricot processing in quail feed: Effects on growth performance, carcass characteristics, and meat physicochemical quality

2021 ◽  
Vol 14 (4) ◽  
pp. 878-883
Author(s):  
Fatma Boubekeur ◽  
Rafik Arbouche ◽  
Yasmine Arbouche ◽  
Fodil Arbouche
Keyword(s):  
Growth Performance ◽  
Soybean Meal ◽  
Average Daily Gain ◽  
Carcass Characteristics ◽  
Live Weight ◽  
Partial Substitution ◽  
Control Group ◽  
Feed Conversion ◽  
Carcass Yield ◽  
By Products

Background and Aim: The rearing of quails can have a stronger attraction for the breeders if we lower the cost prices by introducing by-products in their feed formulas. The aim of this study was to evaluate the effects of the partial substitution of soybean meal by apricot kernel cake (AKC) in the diet of quails, applied either sequentially or during all phases of rearing, on their growth performances, carcass characteristics, and meat physicochemical composition. Materials and Methods: A total of 600 one-day-old quails (Coturnix coturnix japonica), with equal sex ratio and weighing on average 7±0.2 g, were randomly distributed in one control group and three experimental groups, the latter being designed according to the rate of application of AKC in either sequential or non-sequential mode in different rearing phases. Each group was divided into five replicates of 30 quails, randomly distributed according to either substitution rate of soybean meal by the AKC (0%, 10%, 20%, or 30%) or farming phase. Results: The average daily gain from the 1st to 45th days (average daily gain1–45d) was found to be the highest (4.24 g/d/subject, p=0.021) for the 30% AKC-supplemented feed lot in either starter or finish incorporation (DFTAA), having an optimum final live weight of 193.4 g (p=0.028), a lowest feed conversion ratio of 3.08 (p=0.001), and a daily feed intake of 860 g (p=0.01). Carcass yield was recorded the highest (74.4%, p=0.02) with an optimum meat protein level (30.6%, p=0.024) and the lowest fat content (2.26%, p=0.001) for the same group as well. Conclusion: The partial substitution of soybean meal by AKC in the quails' fattening feeding, during the finishing phase and for all rearing phases, led to a better growth performance, a better carcass yield, and an improved chemical composition of meat.

scholarly journals Leucine levels in low protein diets for pigs in the initial phase

2017 ◽  
Vol 38 (6) ◽  
pp. 3829 ◽  
Author(s):  
Laura Marcela Diaz Huepa ◽  
Marcelise Regina Fachinello ◽  
Lucas Antonio Costa Esteves ◽  
Vinicius Ricardo Cambito de Paula ◽  
Silvia Leticia Ferreira ◽  
...  
Keyword(s):  
Crude Protein ◽  
Average Daily Gain ◽  
Blood Parameters ◽  
Backfat Thickness ◽  
Quadratic Model ◽  
Experimental Unit ◽  
Longissimus Dorsi ◽  
Feed Conversion ◽  
Plasma Urea ◽  
Protein Diets

The objective of this study was to evaluate the standardized ileal digestible (SID) leucine levels in low crude protein diets on Performance, backfat thickness, longissimus dorsi depth and biochemical blood parameters of starting pigs. A total of 50 pigs, with initial weight of 11.14±0.24 kg; were distributed in a randomized blocks design with five treatments (1.10; 1.25; 1.40; 1.55 and 1.70% SID leucine), five replicates and two animals per experimental unit, comprised for a barrow and a gilt. The feed conversion ratio (FCR) reduced (P=0.018) due to the increasing SID leucine levels, without affecting other growth performance parameters (final weight, average daily feed intake, average daily gain, backfat thickness, longissimus dorsi depth and lean meat percentage). There was a quadratic effect for plasma triglyceride (P=0.049) and plasma urea (P=0.001). The optimal SID leucine levels obtained for triglycerides and urea were 1.16% and 1.24%, respectively, by associating the quadratic model with the Linear Response Plateu. Low crude protein diets with SID leucine levels up to 1.70% improved the feed conversion with desired urea and triglycerides concentration in blood plasmas achieved at 1.16% and 1.24%, respectively.

scholarly journals PSIV-15 Determining the effects of increasing levels of xylanase in nutrient adequate diets on growth performance, carcass characteristics of growing-finishing pigs

2020 ◽  
Vol 98 (Supplement_3) ◽  
pp. 176-177
Author(s):  
Hayden R Kerkaert ◽  
Joel M DeRouchey ◽  
Steve S Dritz ◽  
Robert D Goodband ◽  
Mike D Tokach ◽  
...  
Keyword(s):  
Growth Performance ◽  
Block Design ◽  
Average Daily Gain ◽  
Carcass Characteristics ◽  
Experimental Unit ◽  
Finishing Pigs ◽  
Carcass Yield ◽  
Distillers Grains With Solubles ◽  
Treatment Data ◽  
Unit Body Weight

Abstract A total of 1,944 mixed sex growing-finishing pigs (PIC; 337×1050; initial BW of 22.5±0.53 kg) were used in a 131-d growth trial to determine the effects of increasing levels of xylanase in adequate diets on grow-finish pig growth performance and carcass characteristics. The 6 dietary treatments consisted of corn, soybean meal, and dried distillers grains with solubles with added xylanase (Belfeed B 1100 MP; Jefo Nutrition Inc., Saint-Hyacinthe, Quebec) formulated to: 0, 5, 10, 20, 40, and 75 of enzymatic activity for xylanase (IU/kg) with 27 pigs per pen and 12 replicates per treatment. Data were analyzed as a randomized complete block design using lmer function in lme4 package in R with pen considered as the experimental unit, body weight as blocking factor, and treatment as a fixed effect. From d 0 to 70, there was a tendency (quadratic, R=0.068) for average daily gain (ADG) to decrease and then increase with increasing added xylanase, but there was no evidence (R &gt;0.10) of differences for average daily feed intake (ADFI) and feed efficiency (G/F). From d 70 to 131 and overall, there was no evidence of difference (R &gt;0.10) observed for ADG, ADFI, and F/G. There was no evidence for difference (R &gt;0.10) between treatments for number of pigs receiving injectable treatments or mortalities. For carcass traits, increasing xylanase increased then decreased (quadratic, R=0.010) percentage carcass yield. Also, as xylanase increased, percentage lean decreased (linear, R=0.038) and backfat marginally increased (linear, R=0.066). In conclusion, adding increasing levels of xylanase in nutrient adequate diets did not influence growth performance or mortality but did improve carcass yield when intermediate levels were fed.

scholarly journals Effect of zilpaterol hydrochloride on the carcass characteristics of Katahdin lamb terminal crosses

2015 ◽  
Vol 2 (2) ◽  
Author(s):  
José Armando Partida-de-la-Peña ◽  
Tania Alejandra Casaya-Rodríguez ◽  
María Salud Rubio-Lozano ◽  
Rubén Danilo Méndez-Medina
Keyword(s):  
Factorial Design ◽  
Crude Protein ◽  
Carcass Characteristics ◽  
Live Weight ◽  
Longissimus Dorsi ◽  
Zilpaterol Hydrochloride ◽  
Fat Thickness ◽  
Dressing Percentage

Zilpaterol hydrochloride (ZH) supplementation (0 vs. 0.15 mg/kg live weight) was evaluated based on the carcass characteristics of Katahdin x Charollais (32 KCh) and Katahdin x Dorper (28 KD) crosses. Lambs were fed a mixed ration with 14% crude protein (CP) and 2.9 Mcal EM/kg DM. Data were analyzed using a completely randomized 2 x 2 factorial design: 2 genotypes (KCh and KD) and 2 ZH levels (0 and 0.15 mg/kg live weight). No interaction was found between ZH and the genotypes. Zilpaterol hydrochloride increased dressing percentage from 52.1 ± 0.3 to 53.7 ± 0.4% (P < 0.001). Animals that received ZH supplementation increased (P < 0.001) the area of their Longissimus dorsi (Ld) by 18.5% and had 7.5% more muscle, 6.0% less bone and 22.4% less fat compared with control lambs (P < 0.05). The breed of the sire had no effect on any of the variables studied. Final pH, fat thickness, conformation and linear carcass measurements did not change with ZH supplementation.

scholarly journals Effects of zinc source and level on growth performance and carcass characteristics of finishing pigs1,2

2019 ◽  
Vol 3 (2) ◽  
pp. 742-748 ◽  
Author(s):  
Henrique S Cemin ◽  
Corey B Carpenter ◽  
Jason C Woodworth ◽  
Mike D Tokach ◽  
Steve S Dritz ◽  
...  
Keyword(s):  
Growth Performance ◽  
Average Daily Gain ◽  
Carcass Characteristics ◽  
Interactive Effects ◽  
Feed Ratio ◽  
Finishing Pigs ◽  
Large White ◽  
Carcass Yield ◽  
Zinc Source ◽  
Quadratic Response

Abstract An experiment was conducted to determine the effects of added Zn source and level on growth performance and carcass characteristics of finishing pigs. A total of 1,980 pigs divided into 2 groups [group 1: 1,008 pigs, TR4 × (Fast Large White × PIC L02) and group 2: 972 pigs, PIC 337 × 1,050], initially 33.3 kg, were used in a 103- or 114-d growth trial in groups 1 and 2, respectively. Treatments were arranged in a 2 × 3 factorial with 2 sources of added Zn, Zn hydroxychloride (ZnHyd; IntelliBond Z, Micronutrients, Indianapolis, IN) or Zn sulfate (ZnSO4), and 3 levels of added Zn (50, 100, or 150 mg/kg). Diets contained a vitamin-trace mineral premix without added Zn and provided 76 and 162 mg/kg Fe and Cu, respectively. All diets contained 750 FTU/kg phytase. There was a total of 14 replicates per treatment. Pens of pigs were weighed approximately every 2 wk to determine average daily gain (ADG), average daily feed intake, and gain-to-feed ratio. At the end of the experiment, pigs were transported to a packing plant to determine hot carcass weight (HCW), backfat depth, loin depth, and lean percentage. Overall, there was no evidence (P &gt; 0.10) for interactive effects of added Zn source and level for growth performance and carcass characteristics. Pigs fed diets with increasing added Zn had a tendency (P = 0.093) for a quadratic response in ADG, with the greatest ADG observed at 100 mg/kg added Zn. There was a linear improvement (P = 0.010) in carcass yield and a quadratic response (P = 0.045) in HCW, with pigs fed 100 mg/kg added Zn having the highest HCW. Pigs fed diets with ZnHyd had improved (P = 0.017) carcass yield and a tendency (P = 0.058) for greater HCW compared with pigs fed ZnSO4. In summary, under the commercial conditions of the study and with diets containing 750 FTU/kg phytase, there were relatively small improvements in ADG of growing-finishing pigs fed added Zn beyond 50 mg/kg. Providing higher levels of added Zn improved carcass characteristics. Zinc source did not influence growth performance, but ZnHyd improved carcass characteristics compared with ZnSO4.

scholarly journals 140 Influence of Enogen Feed Corn and Conventional Yellow Dent Corn in Pelleted or Meal-based Diets on Finishing Pig Performance and Carcass Characteristics

2021 ◽  
Vol 99 (Supplement_1) ◽  
pp. 71-71
Author(s):  
Hadley Williams ◽  
Mike D Tokach ◽  
Jason C Woodworth ◽  
Robert D Goodband ◽  
Joel M DeRouchey ◽  
...  
Keyword(s):  
Growth Performance ◽  
Average Daily Gain ◽  
Carcass Characteristics ◽  
Starch Gelatinization ◽  
Dent Corn ◽  
Conditioning Temperature ◽  
Finishing Pig ◽  
Pig Performance ◽  
Pellet Form ◽  
Main Effects

Abstract Previous research has indicated that starch gelatinization during the pelleting process is greater for Enogen® Feed corn compared to conventional yellow dent corn. Increasing starch gelatinization in the pellet increases the starch digestibility in the pig, which potentially leads to increased growth rate. Therefore, the objective of this study was to determine the effects of feeding Enogen Feed corn in meal or pellet form on finishing pig growth performance and carcass characteristics. A total of 288 pigs (53.0 ± 0.5 kg) were used with 8 pigs/pen and 9 pens/treatment in a 72-d study. Treatments were arranged in a 2×2 factorial with main effects of corn source (Enogen Feed corn or conventional yellow dent corn) and diet form (meal or pellet). Main effects of corn source and diet form as well as their interactions were tested. Pelleting parameters were established with a target conditioner temperature of 82.2°C and corn moisture of 13 to 14%. When pelleting the diets, the conditioning temperature for conventional yellow dent corn averaged 68.4°C and Enogen Feed corn averaged 67.7°C. The hot pellet temperature for conventional yellow dent corn averaged 75.1°C and 75.8°C for Enogen feed corn. For overall performance (d 0 to 72), no interactions between corn source and diet form were observed (P &gt; 0.05). There was a tendency (P &lt; 0.10) for slightly improved average daily gain (ADG) and gain:feed ratio (G:F) for pigs fed conventional yellow dent corn compared to those fed Enogen Feed corn. Pigs fed pelleted diets had increased (P &lt; 0.001) ADG, G:F, and hot carcass weight compared to pigs fed meal diets. In summary, feeding pelleted diets to finishing pigs increased ADG and G:F compared to those fed meal-based diets. There were no major differences observed between corn sources or interactions between corn source and diet form on growth performance.

scholarly journals Effects of coated and noncoated steroidal implants on growth performance, carcass characteristics, and serum estradiol-17β concentrations of finishing Holstein steers

2020 ◽  
Vol 4 (4) ◽  
Author(s):  
Pedro H V Carvalho ◽  
Mariana F Westphalen ◽  
Jonathan A Campbell ◽  
Tara L Felix
Keyword(s):  
Growth Performance ◽  
Animal Health ◽  
Average Daily Gain ◽  
Carcass Characteristics ◽  
Feed Ratio ◽  
Serum Estradiol ◽  
Trenbolone Acetate ◽  
Coated Implant ◽  
Daily Gain ◽  
Estradiol 17Β

Abstract The objectives of the study were to determine the effect of coated or noncoated hormone implants on growth performance, carcass characteristics, and serum estradiol-17β (E2) concentrations of Holstein steers fed a grain-based diet for 112 d. Seventy-nine Holstein steers [average initial body weight (BW) = 452 ± 5.5 kg] were stratified by BW and allotted to one of two treatments: 1) Holstein steers implanted with a coated implant containing 200 mg of trenbolone acetate (TBA) and 40 mg E2 (Revalor-XS (Merck Animal Health; Summit, NJ)] on day 0 (XS) or 2) Holstein steers implanted two times (days 0 and 56) with a noncoated implant containing 80 mg of TBA and 16 mg of E2 [(2IS) Revalor-IS (Merck Animal Health)]. Data were analyzed using the MIXED procedure of SAS (SAS Inst. Inc., Cary, NC). There was no effect (P ≥ 0.71) of implant strategy on initial, middle, and final BW. No effect (P ≥ 0.12) of implant strategy was observed on average daily gain, dry matter intake, or gain-to-feed ratio. There were no effects (P ≥ 0.11) of implant strategy on carcass characteristics. There was an implant × day interaction (P &lt; 0.01) for the circulation of serum E2 concentrations. Serum E2 concentration increased similarly 14 d after Holstein steers were implanted, regardless of implant strategy. At 28 d, after steers were implanted, steers in the XS group had less serum E2 concentration than Holstein steers in the 2IS group. However, at 56 d after the first implantation, both groups, once again, had similar serum E2 concentrations and E2 concentrations were less on day 56 than day 28 for both strategies. Holstein steers implanted with 2IS had greater serum E2 concentration on day 70 and E2 concentrations remained greater than serum E2 of Holstein steers implanted XS for the duration of the trial (day 112). In summary, there was no effect of coated or two doses of noncoated implant on growth performance or carcass characteristics of Holstein steers.

scholarly journals The Impact of Selection using Residual Average Daily Gain and Marbling EPDs on Growth Performance and Carcass Traits in Angus Steers

2019 ◽  
Vol 3 (2) ◽  
Author(s):  
T. R. Krause ◽  
E. R. Moore ◽  
J. Duggin ◽  
J. R. Segers ◽  
T. D. Pringle
Keyword(s):  
Growth Performance ◽  
Feed Efficiency ◽  
Average Daily Gain ◽  
Backfat Thickness ◽  
Feeding Trial ◽  
Body Weights ◽  
Selection For ◽  
Carcass Merit ◽  
The Impact ◽  
Daily Gain

ObjectivesProfitability in the beef industry has narrow margins regulated by revenue from output traits like growth and carcass merit, but profitability is also largely impacted by input expenses like feed costs. Selecting for improvements in feed efficiency during the finishing phase, one of the most feed intensive segments of the industry, can help to mitigate those input costs. This study compared growth performance, feed efficiency, body composition, and carcass characteristics in Angus steers (n = 321) from bulls divergently selected for feed efficiency and marbling.Materials and MethodsAngus sires were selected based on high (10th percentile or better) and low (85th percentile or worse) residual average daily gain (RADG) EPD as well as high (fifth percentile or better) and average (near 50th percentile) marbling (MARB) EPD. These criteria resulted in a 2 × 2 factorial design with four breeding lines: high RADG/high MARB, high RADG/average MARB, low RADG/high MARB, low RADG/average MARB. Data were analyzed using MIXED procedures of SAS with RADG and MARB as main effects. Significance was set at α = 0.05. Generation was also analyzed, where generation one (GEN1) steers were from a selected sire while generation two (GEN2) steers were from a selected sire and a selected dam.ResultsUltrasound and carcass data revealed no differences (P ≥ 0.12) in 12th rib backfat thickness from weaning through slaughter for the RADG EPD groups. Yield grade and dressing percent did not differ (P ≥ 0.56) across RADG or MARB groups. At the beginning and end of the feeding trial, the high RADG (P ≤ 0.02) group had larger ultrasound ribeye area (REA) than the low RADG group. Carcass REA tended (P = 0.08) to be larger in the high versus low RADG steers. During the feedlot trial and through slaughter, body weight was heavier (P ≤ 0.006) for the high versus low RADG steers but did not differ (P ≥ 0.44) across MARB EPD. Feed efficiency measures did not differ (P ≥ 0.32) across RADG or MARB groups apart from the tendency (P = 0.08) for residual feed intake to be lower in the high versus low RADG steers. Marbling scores differed (P ≤ 0.04) across RADG and MARB groups with the low RADG steers and the high MARB steers having improved marbling. The quality grade distribution across MARB EPD revealed that the average MARB steers graded 73% Choice and 25% Prime while the high MARB steers graded 56% and 42%, respectively. Slice shear force did not differ (P ≥ 0.32) across RADG or MARB EPD. Body weights tended (P = 0.06) to be heavier at the start of the feeding trial for GEN1 versus GEN2 steers. Total gain, average daily gain, and feed to gain (F:G) differed by generation (P ≤ 0.007) with increased rates of gain and reduced F:G in the GEN2 versus GEN1 steers. Body weights did not differ (P = 0.72) across GEN at the end of the feeding trial. Backfat thickness at the start and end of the feedlot phase was less (P ≤ 0.03) and marbling score was improved (P = 0.02) in the GEN2 versus GEN1 steers, respectively.ConclusionThese results suggest that selection using RADG EPD has negligible impacts on meat quality; and that progress in selection for efficiency can be achieved while advancing carcass quality and value. Furthermore, continued divergent selection for feed efficiency and marbling has the potential to improve feed efficiency through advancements in the rate of gain, while enhancing carcass merit through marbling.

scholarly journals Effects of restricted feeding and re-alimentation of dietary protein or energy on compensatory growth of sheep

1970 ◽  
Vol 47 (3) ◽  
pp. 389-396
Author(s):  
W. Addah ◽  
A. Ayantunde ◽  
E.K. Okine
Keyword(s):  
Growth Performance ◽  
Dietary Protein ◽  
Feed Efficiency ◽  
Average Daily Gain ◽  
Carcass Characteristics ◽  
High Energy ◽  
Utilization Efficiency ◽  
Eating Quality ◽  
Nutrient Utilization Efficiency ◽  
Daily Gain

The study investigated the effects of re-alimenting dietary protein or energy on growth, carcass characteristics and meat eating quality parameters of sheep. Twenty-seven intact rams (~9 months; 11.3 ± 0.5 kg) were randomly divided into three groups. Each group was fed a maintenance diet (MT) containing, on dry matter (DM) basis, 105 g/kg crude protein (CP) and 8.4 MJ/kg DM metabolizable energy (ME) for 30 days. Thereafter, they were continually fed the same MT or re-alimented with a high protein diet (HP) containing 169 g/kg DM CP and 9.3 MJ/kg ME or a high energy diet (HE) containing 123 g/kg DM CP and 10.6 MJ/kg ME for an additional 30 days to determine the effects of re-alimentation of protein or energy on their growth performance and carcass characteristics. During the initial 30-day period, DM intake (DMI) and growth performance were similar among the three groups. However, upon re-alimentation, average daily gain (ADG) and feed efficiency of sheep re-alimented with HP were greater than those maintained continually on MT or re-alimented with HE. Sheep on HP had higher feed efficiency, ADG and heavier carcasses than those fed MT or re-alimented with HE during the whole 60-day period. Growth of most viscera was less responsive to the restriction-re-alimentation feeding regimen except for the weights of the lungs, heart and intestines. Meat from sheep re-alimented with HE had a more intense ‘sheepy’ flavour than those fed MT or re-alimented with HP, but juiciness and tenderness were not affected. The higher ADG of sheep re-alimented with protein may be related more to enhanced efficiency of feed utilization than to higher DMI.Keywords: average daily gain, feed restriction, nutrient utilization efficiency, visceral organs

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