Karim S A, Porwal Kuldeep, Kumar Suresh, Singh V K
Division of Animal Nutrition, Central Sheep and Wool Research Institute, Avikanagar 304 501, Rajasthan, India.
Meat Sci. 2007 Jul;76(3):395-401. doi: 10.1016/j.meatsci.2006.06.008. Epub 2007 Apr 6.
The study was conducted on 6-month-old finisher lambs of the Kheri breed raised under extensive range management (G1), grazing with ad libitum concentrate supplementation (G2) or intensive feeding (G3) to assess dressing yield, cutability of standard cuts, composition of the carcass and the efficiency of mutton production from the three defined systems. The weaning weight of the lambs in the three groups was similar while the finishing weight, total body weight gain in the experiment, average daily gain and the percent feed conversion efficiency were higher (P<0.01) in G2 and G3 than G1. The pre slaughter weight (PSW), empty live weight (ELW), hot carcass weight and hot carcass weight with edible offal was higher (P<0.01) in G2 and G3 fed on a high plane of nutrition than G1 raised under extensive range management. The dressing percent in terms of live weight (LW) and empty live weight (ELW) was also higher in G2 and G3 than G1. The loin eye area as an index of muscle growth was also higher in G2 and G3 than G1. Although the weights of standard cuts were generally higher in G2 and G3 due to higher PSW, as proportions of half carcass they were similar in the three groups, except the rack cut, which was higher in G2 and G3. The cut proportions pooled for the three groups averaged 33.2%, 12.3%, 13.3%, 24.9% and 16.3% of half carcass for leg, loin, rack, neck and shoulder and breast and fore shank, respectively. The depot fat (Caul and kidney fat) accretion was higher in G2 and G3 than G1. The composition of the half carcass indicated that lean percent was higher (P<0.01) in G1 and G2 than G3 while sub cutaneous and intra muscular fat content were generally higher (P<0.01) in G2 and G3 and KOH bone percent was higher (P<0.05) in G1 and G2 than G3. The results indicated that the growth performance was better, feed conversion efficiency, carcass yield and dressing percentage higher in lambs maintained under grazing with supplementation and intensive feeding than extensive range management. The carcass separable fat content was 8% under extensive range management while it was 12% and 16% in semi intensive and intensive system of feeding management indicating that the carcass was of acceptable quality. The loin eye area reflected the trends of pre slaughter weight and was higher in intensive and semi intensive than extensive range management.
本研究以6月龄的凯瑞品种育成羔羊为对象，这些羔羊分别采用粗放型放牧管理（G1组）、自由采食精料补饲的放牧方式（G2组）或集约化饲养方式（G3组），以评估三种既定饲养体系下的屠宰率、标准切块的可切割性、胴体组成以及羊肉生产效率。三组羔羊的断奶体重相似，但G2组和G3组的育肥体重、实验期间的总体重增加、平均日增重和饲料转化效率百分比均高于G1组（P<0.01）。在高营养水平下饲养的G2组和G3组，其宰前体重（PSW）、空腹活重（ELW）、热胴体重以及带可食用内脏的热胴体重均高于采用粗放型放牧管理的G1组（P<0.01）。G2组和G3组以活重（LW）和空腹活重（ELW）计算的屠宰率也高于G1组。作为肌肉生长指标的眼肌面积，G2组和G3组也高于G1组。尽管由于宰前体重较高，G2组和G3组标准切块的重量一般更高，但作为半胴体的比例，三组相似，除了肋排切块，G2组和G3组的肋排切块比例更高。三组汇总的切块比例中，腿、腰、肋排、颈、肩以及胸和前小腿占半胴体的比例分别平均为33.2%、12.3%、13.3%、24.9%和16.3%。G2组和G3组的贮藏脂肪（网膜和肾周脂肪）蓄积高于G1组。半胴体组成表明，G1组和G2组的瘦肉率高于G3组（P<0.01），而G2组和G３组的皮下脂肪和肌内脂肪含量一般更高（P<0.01），G1组和G2组的氢氧化钾法测定的骨含量高于G3组（P<0.05）。结果表明，与粗放型放牧管理相比，补饲放牧和集约化饲养方式下的羔羊生长性能更好，饲料转化效率、胴体产量和屠宰率更高。粗放型放牧管理下胴体可分离脂肪含量为8%，而半集约化和集约化饲养管理体系下分别为12%和16%，表明胴体质量合格。眼肌面积反映了宰前体重的趋势，集约化和半集约化饲养方式下的眼肌面积高于粗放型放牧管理。
