Enright W J, Quirke J F, Gluckman P D, Breier B H, Kennedy L G, Hart L C, Roche J F, Coert A, Allen P
Dept. of Anim. Nutr. and Physiol., Teagasc, Grange Research Centre, Ireland.
J Anim Sci. 1990 Aug;68(8):2345-56. doi: 10.2527/1990.6882345x.
Sixty-three Friesian steers (9 mo old, 257 kg; n = 15 or 16/treatment) were employed in a 2 x 2 factorial to test bovine growth hormone (bGH) and estradiol (Compudose implant). Steers received daily subcutaneous injections of vehicle or bGH (40 micrograms/kg body weight) for 22 wk. Steers were slaughtered 8 wk after the end of bGH treatment (wk 30). Steers had ad libitum access to silage plus a fixed amount (4 to 5.5 kg/d) of concentrate. Average daily gain (ADG) and feed conversion efficiency (FCE) improved (P less than .05) in response both to bGH and to estradiol during wk 0 to 22. Although bGH did not affect ADG or FCE during wk 23 to 30, estradiol improved (P less than .05) them; bGH and estradiol appeared additive (nonsignificant interactions) during wk 0 to 22. At slaughter, estradiol increased (P less than .05) carcass weight and carcass and leg length while decreasing (P less than .05) conformation score and percentage of kidney, knob and channel fat (KHP); bGH decreased (P less than .05) KHP. Although both bGH and estradiol increased (P less than .01) plasma GH, their effects were not additive. Both bGH and estradiol increased (P less than .01) plasma somatomedin-C and decreased (P less than .01) plasma urea nitrogen concentrations; effects were additive. Estradiol, but not bGH, increased (P less than .05) plasma glucose, whereas neither bGH nor estradiol altered plasma creatinine and nonesterified fatty acids. In summary, both bGH and estradiol improved growth and FCE, and their effects appeared to be additive. It is likely that some of their effects were mediated by somatomedin-C.
选用63头弗里生公牛（9月龄，体重257千克；每组15或16头），采用2×2析因试验来检测牛生长激素（bGH）和雌二醇（复方孕酮埋植剂）的作用。公牛连续22周每天皮下注射赋形剂或bGH（40微克/千克体重）。在bGH治疗结束后8周（第30周）将公牛屠宰。公牛可自由采食青贮饲料，并每日定量采食4至5.5千克精饲料。在第0至22周期间，bGH和雌二醇均使平均日增重（ADG）和饲料转化效率（FCE）提高（P<0.05）。虽然在第23至30周期间bGH对ADG和FCE无影响，但雌二醇使其提高（P<0.05）；在第0至22周期间，bGH和雌二醇的作用似乎具有相加性（无显著交互作用）。屠宰时，雌二醇使胴体重、胴体及腿长增加（P<0.05），同时使体型评分以及肾、会阴和通道脂肪（KHP）百分比降低（P<0.05）；bGH使KHP降低（P<0.05）。虽然bGH和雌二醇均使血浆生长激素升高（P<0.01），但其作用并非相加性。bGH和雌二醇均使血浆生长调节素-C升高（P<0.01），并使血浆尿素氮浓度降低（P<0.01）；作用具有相加性。雌二醇使血浆葡萄糖升高（P<0.05），而bGH无此作用，bGH和雌二醇均未改变血浆肌酐和非酯化脂肪酸水平。总之，bGH和雌二醇均改善了生长和FCE，且其作用似乎具有相加性。它们的某些作用可能是由生长调节素-C介导的。
