Williams J E, Miller S J, Mollett T A, Grebing S E, Bowman D K, Ellersieck M R
University of Missouri, Columbia 65211.
J Anim Sci. 1987 Oct;65(4):1113-23. doi: 10.2527/jas1987.6541113x.
A 2 X 2 factorially arranged trial was conducted to compare effects of implant (zeranol) and frame size on weight and compositional gain, and plasma hormone concentrations. Angus, Charolais X Hereford and Hereford X Angus yearling steers (34 steers averaging 270 kg body weight) were randomly assigned to treatments of small (SF) vs large frame (LF) and implant (I) vs no implant (NI). Steers were implanted at 0 and 97 d and individually fed an 81% whole shelled corn and 11.5% corn silage-based diet (dry basis) for a 175-d period. Shrunk weights and body measurements for frame size determination were taken initially and at approximately 28-d intervals; blood was collected via venipuncture at 14-d intervals for analyses of insulin (IN), triiodothyronine (T3), thyroxine (T4) and glucose concentrations. Steers were also counted in a whole body counter for measurement of 40K content and prediction of whole body protein and fat. The I steers showed an improvement (P less than .05) in daily gain regardless of frame size for the total trial. The I LF steers required 18% more dry matter to attain higher daily gain for 97 to 175 d; I steers were more efficient (P less than .05) at converting dry matter to gain during 0 to 97 d and 0 to 175 d. Daily fat deposition was increased (P less than .05) in I steers, while protein deposition was not affected by I. Plasma IN concentrations were numerically elevated (P less than .10) in I steers regardless of frame size, during the initial 97 d. Implant did not influence (P greater than .10) plasma T3, T4 and glucose concentrations regardless of frame size. Steers responded differently to zeranol implant over time regarding plasma T4 concentrations (P less than .003). Steers differing in frame size responded similarly in rate of gain, in feed conversion and in patterns of plasma insulin concentrations to zeranol implants.
进行了一项2×2析因试验，以比较植入物（玉米赤霉醇）和体格大小对体重、成分增加以及血浆激素浓度的影响。安格斯牛、夏洛来×赫里福德杂交牛和赫里福德×安格斯杂交一岁公牛（34头，平均体重270千克）被随机分配到小体格（SF）与大体格（LF）以及植入（I）与不植入（NI）的处理组。公牛在第0天和第97天进行植入，并在175天的时间里单独饲喂以81%整粒脱壳玉米和11.5%玉米青贮为基础的日粮（干基）。最初以及每隔约28天测量收缩体重和体格大小的身体测量数据；每隔14天通过静脉穿刺采集血液，用于分析胰岛素（IN）、三碘甲状腺原氨酸（T3）、甲状腺素（T4）和葡萄糖浓度。还使用全身计数器对公牛进行计数，以测量40K含量并预测全身蛋白质和脂肪含量。在整个试验中，无论体格大小，植入组公牛的日增重均有所改善（P＜0.05）。植入组大体格公牛在第97至175天需要多18%的干物质才能获得更高的日增重；植入组公牛在第0至97天和第0至175天将干物质转化为增重的效率更高（P＜0.05）。植入组公牛的日脂肪沉积增加（P＜0.05），而蛋白质沉积不受植入物影响。在最初的97天内，无论体格大小，植入组公牛的血浆IN浓度在数值上均有所升高（P＜0.10）。无论体格大小，植入物均未影响（P＞0.10）血浆T3、T4和葡萄糖浓度。随着时间的推移，公牛对玉米赤霉醇植入物的血浆T4浓度反应不同（P＜0.003）。体格大小不同的公牛在增重速度、饲料转化率和血浆胰岛素浓度模式方面对玉米赤霉醇植入物的反应相似。
