Woods B L, Bradley N W, Schillo K K, Lowry S R
Dept. of Anim. Sci., University of Kentucky, Lexington 40546-0215.
J Anim Sci. 1990 Apr;68(4):919-22. doi: 10.2527/1990.684919x.
An experiment was conducted to evaluate the effects of breed, sex and plane of nutrition on the growth response to zeranol in Angus and crossbred calves prior to weaning. Eighty-eight heifers and 118 steers received either a high or low plane of nutrition using a first and last grazing technique. Half of the calves in each nutrition group received a zeranol implant (36 mg) at an average age of 3.4 mo. Both zeranol and the higher level of nutrition increased (P less than .001) growth rate prior to weaning (7.4 mo of age). Zeranol did not affect hip height at weaning (P greater than .1), but calves on the higher plane of nutrition were taller (P less than .01) than calves on the lower plane of nutrition. The zeranol x nutrition interaction was not significant (P greater than .1) for growth rate or hip height. Steers grew faster (P less than .01) preweaning and were taller (P less than .01) at weaning than heifers. Crossbred calves gained more rapidly (P less than .001) preweaning and were taller (P less than .001) at weaning than Angus calves were. Neither sex nor breed interacted with zeranol to influence any of the traits examined. Based on these results we conclude that preweaning growth was affected by zeranol and this effect was consistent across sexes, breeds and planes of nutrition tested.
进行了一项实验，以评估品种、性别和营养水平对安格斯犊牛和杂交犊牛断奶前对玉米赤霉醇生长反应的影响。88头小母牛和118头小公牛采用首次和末次放牧技术，分别接受高营养水平或低营养水平的饲养。每个营养组中一半的犊牛在平均年龄3.4月龄时接受一次玉米赤霉醇植入（36毫克）。玉米赤霉醇和较高的营养水平均提高了（P<0.001）断奶前（7.4月龄）的生长速度。玉米赤霉醇对断奶时的髋高没有影响（P>0.1），但营养水平较高组的犊牛比营养水平较低组的犊牛更高（P<0.01）。玉米赤霉醇与营养水平的交互作用对生长速度或髋高均无显著影响（P>0.1）。小公牛断奶前生长更快（P<0.01），断奶时也比小母牛更高（P<0.01）。杂交犊牛断奶前增重更快（P<0.001），断奶时也比安格斯犊牛更高（P<0.001）。性别和品种与玉米赤霉醇之间均无交互作用来影响所检测的任何性状。基于这些结果，我们得出结论，断奶前生长受玉米赤霉醇影响，且这种影响在受试的性别、品种和营养水平中是一致的。
