Hormonal Development of the Mammary Gland of Dairy Heifers

Abstract

Accelerated mammary gland development has been produced in very young dairy heifers with injns. of stilbestrol, progesterone and crude pituitary extract. The type of development and sequence of developmental stages produced by stilbestrol or stilbestrol plus progesterone were distinctly modified by the addition of pituitary extract. The pituitary extract accentuated the effects of steroid hormones. Progesterone, in the dosage employed, had no detectable effect on mammary development. Injn. of the various hormones produced an inhibition of endogenous hormone secretion.