Shaw G H, Convey E M, Tucker H A, Reineke E P, Thomas J W, Byrne J J
J Dairy Sci. 1975 May;58(5):703-8. doi: 10.3168/jds.S0022-0302(75)84631-5.
Twenty-one lactating Holstein cows were assigned randomly to groups of seven and received: (1) no treatment; (2) 15 g thyroprotein daily for 5 wk; or (3) 15 g thyroprotein daily for 13 wk. Combined averages for serum thyroxine of cows in thyroprotein groups increased linearly from a baseline of 54 ng/ml to a peak of 135 ng/ml at 6 days after thyroprotein feeding was begun. Serum thyroxine then decreased to approximately 80 ng/ml at 23 days of thyroprotein feeding which was maintained during the remainder of the feeding period. Following thyroprotein withdrawal from the diet serum thyroxine concentration decreased to 24 ng/ml at 6 days. Neither serum prolactin, growth hormone, nor total glucocorticoids were affected by thyroprotein feeding or withdrawal. Average milk production of cows in the control group decreased linearly with time. Milk production of cows fed thyroprotein for 5 wk averaged 2.2 to 3.3 kg/day more than cows in the control group and that of cows fed thyroprotein for 13 wk averaged .95 to 2.5 kg/day more than controls for 60 days, but between 60 and 91 days it was .9 kg/day less than controls.
21头泌乳期荷斯坦奶牛被随机分为7头一组，并接受以下处理：(1) 不做处理；(2) 每天饲喂15克甲状腺蛋白，持续5周；或(3) 每天饲喂15克甲状腺蛋白，持续13周。甲状腺蛋白组奶牛的血清甲状腺素综合平均值从54纳克/毫升的基线水平开始呈线性增加，在开始饲喂甲状腺蛋白6天后达到135纳克/毫升的峰值。然后血清甲状腺素在饲喂甲状腺蛋白23天时降至约80纳克/毫升，并在剩余的饲喂期内维持该水平。从日粮中撤掉甲状腺蛋白后，血清甲状腺素浓度在6天时降至24纳克/毫升。血清催乳素、生长激素和总糖皮质激素均未受到甲状腺蛋白饲喂或撤料的影响。对照组奶牛的平均产奶量随时间呈线性下降。饲喂甲状腺蛋白5周的奶牛产奶量平均比对照组奶牛每天多2.2至3.3千克，饲喂甲状腺蛋白13周的奶牛在60天内平均比对照组多0.95至2.5千克/天，但在60至91天期间比对照组少0.9千克/天。
