Sejrsen K, Huber J T, Tucker H A
J Dairy Sci. 1983 Apr;66(4):845-55. doi: 10.3168/jds.S0022-0302(83)81866-9.
Concentrations in blood serum of growth hormones, prolactin, insulin, and glucocorticoids were investigated in 22 pre- or postpubertal heifers fed restricted or ad libitum amounts of a ration. Gains for the respective feeding regimens were 613 and 1218 g daily. Growth hormone was elevated for prepubertal heifers on restricted feed, whereas there was no difference from feeding for postpubertal heifers. Concentrations of prolactin, insulin, and glucocorticoids were higher for heifers fed ad libitum than for those restricted. Mammary secretory tissue was positively correlated with blood serum concentrations of growth hormone, and extraparenchymal adipose tissue was negatively correlated with them. Prolactin was negatively related to mammary secretory tissue; however, this relationship disappeared after adjustment for concentrations of growth hormone, insulin, and glucocorticoids. Mammary tissue was not related to concentrations of insulin or glucocorticoids. The negative influence of excess feeding on mammary development of prepubertal heifers may be associated with a decrease in concentrations of growth hormone in blood.
对22头青春期前或青春期后的小母牛进行了研究，这些小母牛分别以限量或不限量的方式进食一种日粮，测定了它们血清中生长激素、催乳素、胰岛素和糖皮质激素的浓度。各自饲养方案下的日增重分别为613克和1218克。青春期前的小母牛在限量饲养时生长激素升高，而青春期后的小母牛在不同饲养方式下没有差异。不限量饲养的小母牛的催乳素、胰岛素和糖皮质激素浓度高于限量饲养的小母牛。乳腺分泌组织与血清生长激素浓度呈正相关，实质外脂肪组织与血清生长激素浓度呈负相关。催乳素与乳腺分泌组织呈负相关；然而，在对生长激素、胰岛素和糖皮质激素浓度进行校正后，这种关系消失了。乳腺组织与胰岛素或糖皮质激素浓度无关。过量饲养对青春期前小母牛乳腺发育的负面影响可能与血液中生长激素浓度降低有关。
