Bishop M D, Davis M E, Harvey W R, Wilson G R, VanStavern B D
Anim. Sci. Dept., Ohio State University, Columbus 43210.
J Anim Sci. 1991 Nov;69(11):4348-59. doi: 10.2527/1991.69114348x.
Each year from 1979 through 1983, 35 Angus bull calves were selected from a herd at the Eastern Ohio Resource Development Center to be individually fed in a 140-d postweaning performance test. From these 35 individually fed bulls, the three highest and three lowest for feed conversion (feed:gain) were selected and randomly mated to approximately 20 cows each. A different set of high vs low feed conversion sires was used each year. Four replicates (403 progeny) from high vs low sires were evaluated by sire groups for subsequent postweaning and carcass performance. Progeny were slaughtered when estimated by ultrasonic measurement to have 8.9 mm or more of subcutaneous fat at the conclusion of a 140-d postweaning performance test. Progeny with less than 8.9 mm of subcutaneous fat were fed for additional 28-d periods until they reached the required minimum. No differences were found between high and low feed conversion progeny for 140-d feed intake (P less than .30) although high feed conversion progeny gained .09 kg/d more weight (P less than .01) during the 140-d postweaning test. Differences tended to exist between high and low feed conversion progeny for unadjusted (P less than .15) and maintenance-adjusted (P less than .15) feed:gain ratios. Progeny of the high feed conversion group had greater subcutaneous fat (P less than .05) at the end of the 140-d postweaning test and when slaughtered (P less than .05), indicating a genetic difference for composition of BW gain between high- and low-sired progeny. However, no significant differences existed for any other carcass traits evaluated. Bulls had more desirable unadjusted (P less than .001) and maintenance-adjusted (P less than .001) feed:gain ratios than heifers with increased 140-d ADG (P less than .001) and pen feed intakes (P less than .001).
从1979年到1983年，每年从俄亥俄州东部资源开发中心的一个牛群中挑选35头安格斯公牛犊，在断奶后140天的性能测试中单独饲养。从这35头单独饲养的公牛中，挑选出饲料转化率（饲料：增重）最高的三头和最低的三头，分别随机与大约20头母牛交配。每年使用不同的高饲料转化率与低饲料转化率的种公牛组合。对高、低种公牛的四个重复组（403头后代）按种公牛组评估断奶后和胴体性能。在断奶后140天性能测试结束时，通过超声波测量估计皮下脂肪达到8.9毫米或更多的后代进行屠宰。皮下脂肪少于8.9毫米的后代再饲养28天，直到达到所需的最低标准。高、低饲料转化率后代在140天的采食量方面没有差异（P小于0.30），尽管高饲料转化率后代在断奶后140天的测试中每天增重多0.09千克（P小于0.01）。高、低饲料转化率后代在未调整（P小于0.15）和维持调整（P小于0.15）的饲料：增重比方面存在差异趋势。高饲料转化率组的后代在断奶后140天测试结束时和屠宰时皮下脂肪更多（P小于0.05），表明高、低种公牛后代在体重增加组成方面存在遗传差异。然而，在评估的任何其他胴体性状方面没有显著差异。公牛的未调整（P小于0.001）和维持调整（P小于0.001）饲料：增重比比小母牛更理想，140天平均日增重（P小于0.001）和栏内采食量增加（P小于0.001）。
