Granger A L, Wyatt W E, Hembry F G, Craig W M, Thompson D L
Department of Animal Science, Louisiana State University Agricultural Center, Baton Rouge 70893.
J Anim Sci. 1990 Feb;68(2):304-16. doi: 10.2527/1990.682304x.
Fifteen spring-born Angus (AN) and 25 Brangus (BN) weanling heifers were used in a 2x5 factorial arrangement of treatments to evaluate the effects of breed and postweaning winter diet on heifer growth and development. Dietary treatments were warm-season perennial grass hay (H), ammoniated H (AH), H plus .68 kg/d cottonseed meal (HP), H plus .45 kg/d cottonseed meal plus 1.37 kg/d ground corn (HPE) and HPE plus 200 mg/d monensin (HPEM). Mean initial weight and age for the 107-d feed trial were 207 kg and 270 d. Brangus had .06 kg greater (P less than .05) ADG than AN during the trial. Although digestible DM intake (DDMI) relative to body weight was greater (P less than .10) for AN than for BN, ADG:DDMI was greater (P less than .05) for BN than for AN. Heifers fed H and AH lost weight, but heifers fed AH had 50% (P less than .05) less daily weight loss than those fed H. Daily gain increased (P less than .05) incrementally in response to sequential supplement additions of cottonseed meal (AH vs HP; -.10 vs .17 kg), ground corn (HP vs HPE; .17 vs .29 kg) and monensin (HPE vs HPEM; .29 vs .39 kg). Hay DM intake relative to body weight and DDMI were increased (P less than .01) by ammoniation. Intake did not differ between HPE and HPEM. Diet affected age at puberty (P less than .05), which decreased with increased dietary components. Weight differences among diet groups following the winter feed trial were largely eliminated prior to breeding. Nevertheless, H- and AH-fed heifers collectively weighed less (P less than .01) prior to breeding than did heifers of supplemented diet groups. Reproductive development tended to be adversely affected by weight loss during the postweaning period.
选用15头春季出生的安格斯（AN）断奶小母牛和25头婆罗格斯（BN）断奶小母牛，采用2×5析因处理设计，以评估品种和断奶后冬季日粮对小母牛生长发育的影响。日粮处理包括暖季多年生牧草干草（H）、氨化干草（AH）、H加0.68千克/天棉籽粕（HP）、H加0.45千克/天棉籽粕加1.37千克/天碎玉米（HPE）以及HPE加200毫克/天莫能菌素（HPEM）。107天饲养试验的平均初始体重和年龄分别为207千克和270天。试验期间，婆罗格斯的平均日增重（ADG）比安格斯高0.06千克（P＜0.05）。尽管安格斯相对于体重的可消化干物质摄入量（DDMI）比婆罗格斯高（P＜0.10），但婆罗格斯的ADG:DDMI比安格斯高（P＜0.05）。采食H和AH的小母牛体重减轻，但采食AH的小母牛日体重损失比采食H的小母牛少50%（P＜0.05）。随着依次添加棉籽粕（AH对HP；-0.10对0.17千克）、碎玉米（HP对HPE；0.17对0.29千克）和莫能菌素（HPE对HPEM；0.29对0.39千克），日增重呈递增增加（P＜0.05）。氨化处理使干草相对于体重的干物质摄入量和DDMI增加（P＜0.01）。HPE和HPEM的摄入量无差异。日粮影响初情期年龄（P＜0.05），初情期年龄随日粮成分增加而降低。冬季饲养试验后各日粮组之间的体重差异在配种前基本消除。然而，配种前采食H和AH的小母牛总体重比采食补充日粮组的小母牛轻（P＜0.01）。断奶后体重减轻往往对繁殖发育产生不利影响。
