Istasse L, Evrard P, Van Eenaeme C, Gielen M, Maghuin-Rogister G, Bienfait J M
Faculte de Med. Vet., Universite de Liege, Bruxelles.
J Anim Sci. 1988 May;66(5):1212-22. doi: 10.2527/jas1988.6651212x.
Twelve (Exp. 1) and 24 (Exp. 2) young growing bulls were used to compare the effects of long-acting, cholesterol-based implants with short-acting, lactose-based implants. Each implant contained 200 mg of trenbolone acetate and 40 mg of 17 beta-estradiol. The long-acting, cholesterol-based implants were applied once either 18 wk (early implantation) or 12 wk (late implantation) before slaughter. The lactose-based pellets were implanted once (6 wk before slaughter), twice (12 and 6 wk) or three times (18, 12 and 6 wk) before slaughter. Treated animals had higher live weight gains, a lower feed conversion ratio, a higher proportion of lean meat and a lower proportion of adipose tissue than control animals. In Exp. 1 live weight gain of bulls implanted early with a single cholesterol-based implant was similar to the gain of animals treated three times with a lactose-based implant, but in Exp. 2 the effects of the long-acting implants given early were not sustained. In Exp. 3, 24 young growing bulls were used in a 3 X 2 factorial design to compare the effects of three dose levels of trenbolone acetate (100, 200 and 300 mg) and two levels of 17 beta-estradiol (40 and 60 mg). There were no significant differences between treatment groups, but highest live weight gains were observed in animals implanted with 300 mg of trenbolone and 60 mg of estradiol. This group also yielded the highest proportion of lean meat and the lowest proportion of adipose tissue. There was a decrease in plasma urea concentration after each implantation. It appeared also that plasma trenbolone was higher with implants containing 60 mg of estradiol. There were no differences between groups in growth hormone response to arginine stimulation.
选用12头（实验1）和24头（实验2）生长中的年轻公牛，比较长效、基于胆固醇的植入物与短效、基于乳糖的植入物的效果。每种植入物含有200毫克醋酸群勃龙和40毫克17β -雌二醇。长效、基于胆固醇的植入物在屠宰前18周（早期植入）或12周（晚期植入）施用一次。基于乳糖的微丸在屠宰前植入一次（屠宰前6周）、两次（12周和6周）或三次（18周、12周和6周）。与对照动物相比，处理过的动物有更高的活体重增加、更低的饲料转化率、更高的瘦肉比例和更低的脂肪组织比例。在实验1中，早期单次植入基于胆固醇的植入物的公牛的活体重增加与用基于乳糖的植入物处理三次的动物的增加相似，但在实验2中，早期给予的长效植入物的效果没有持续。在实验3中，24头生长中的年轻公牛用于3×2析因设计，以比较三种剂量水平的醋酸群勃龙（100、200和300毫克）和两种水平的17β -雌二醇（40和60毫克）的效果。处理组之间没有显著差异，但在植入300毫克醋酸群勃龙和60毫克雌二醇的动物中观察到最高的活体重增加。该组还产生了最高比例的瘦肉和最低比例的脂肪组织。每次植入后血浆尿素浓度降低。似乎含60毫克雌二醇的植入物的血浆群勃龙也更高。各组对精氨酸刺激的生长激素反应没有差异。
