Murphy T A, Loerch S C, McClure K E, Solomon M B
Department of Animal Science, Ohio Agricultural Research and Development Center, Ohio State University, Wooster 44691.
J Anim Sci. 1994 Dec;72(12):3131-7. doi: 10.2527/1994.72123131x.
Fifty-eight crossbred lambs (26 kg BW) with moderate growth potential were used in a completely randomized design experiment to determine the effects of restricted feeding of all-concentrate diets on performance and carcass composition. Feeding levels studied were 100, 85, and 70% of ad libitum intake. Diets that were restricted-fed were formulated to have increased nutrient concentrations to provide equal daily intakes of protein, vitamins, and minerals among DM intake levels. Lambs were fed to a final weight that would yield carcasses of equal weight (24 kg). Average daily gain was reduced linearly (P < .02) and days on feed were increased linearly (P < .02) because of restricted feeding. Feed efficiency, however, was not affected by intake level. The quantity of separable lean tissue within carcass sides was increased (P < .05) with restricted feeding. Total separable fat within the side was reduced (P < .05) in an amount equal to the increase in lean tissue accretion. Chemical analysis of the carcass side showed a decrease (P < .05) in fat percentage and a corresponding increase (P < .05) in water percentage because of restricted feeding. Daily accretion rates of lean and bone tissue were not affected by restricted feeding; however, fat accretion was decreased linearly with decreasing feeding levels. Separable lean tissue within the primal cuts was generally increased with decreasing intakes, which led to a corresponding decrease in separable fat. Restricted feeding strategies can lead to the production of leaner carcasses. Reductions in fat content occur in the subcutaneous, seam, and mesenteric depot sites, but intramuscular fat content of consumable product also is reduced.
选用58只具有中等生长潜力的杂交羔羊（体重26千克），进行完全随机设计实验，以确定全精料日粮限饲对生长性能和胴体组成的影响。所研究的饲喂水平分别为随意采食量的100%、85%和70%。限饲日粮的营养浓度较高，以确保不同干物质采食量水平下的蛋白质、维生素和矿物质日摄入量相等。将羔羊饲养至最终体重，使其胴体重量相等（24千克）。限饲导致平均日增重呈线性下降（P < 0.02），采食天数呈线性增加（P < 0.02）。然而，饲料效率不受采食量水平的影响。限饲使胴体侧部可分离瘦肉组织量增加（P < 0.05）。侧部总可分离脂肪量减少（P < 0.05），减少量与瘦肉组织生长量的增加量相等。胴体侧部的化学分析表明，限饲使脂肪百分比降低（P < 0.05），水分百分比相应增加（P < 0.05）。限饲不影响瘦肉和骨骼组织的日生长率；然而，脂肪生长率随饲喂水平的降低呈线性下降。随着采食量的减少，主要切块中的可分离瘦肉组织通常会增加，相应地可分离脂肪会减少。限饲策略可使胴体更瘦。皮下、肌间和肠系膜脂肪储存部位的脂肪含量降低，但可食用产品的肌内脂肪含量也会降低。
