Induction of Lactation in Heifers with the Hypophyseal Lactogenic Hormone. ∗

Abstract

We present here results of preliminary experiments on the possibility of producing lactation in the virgin heifer by the injection of the hypophyseal lactogenic hormone. A 1% solution of crude lactogenic hormone† prepared from bovine anterior lobes was used. We employed 2 Holstein heifers 16 months old and 2 Ayrshire heifers 12 months old.

Holstein Experiments. The udders of these animals H-l and H-2 were manipulated twice daily for 1 week. At the end of this time H-l showed a very slight serous secretion. 10.0 cc. of the hormone were then injected subcutaneously daily for 11 days into this animal. The secretion became milky on the fourth day of injection and increased rapidly in amount up to 500 cc. daily by the eleventh day when milking was stopped and the heifer allowed to go dry. Through the courtesy of Dr. G. A. Richardson of the Division of Dairy Industry, University of California at Davis, samples of the tenth and eleventh days secretions were analyzed. The fat content, pH, and co-agulation times of the milks were within the usual limits of variation. Without knowledge of the source, the flavor was criticized as “not definitely pleasing”. The most prominent taste was salty, due to low lactose and high chloride content. The consistency of the milk was somewhat thick, probably due to the high protein content. Peroxidase was present. It was agreed that in the course of 10 days the hormone had induced a secretion at least sensibly approaching normal constitution, and we would expect the discrepancies to vanish should the milk secreting mechanism get fully under way with continued treatment.

The control animal H-2 was manipulated daily for 22 days. A few drops of a salty, serous fluid could be expressed on the 15th day and after. Beginning on the twenty-second day, a total of 100 cc. hormone was injected over a period of 13 days. By the tenth day the secretion was milky in appearance. On each of the fourteenth and fifteenth days about 250 cc. of milk were obtained. Milking was continued until the eighteenth day, when the secretion had begun to fall off in amount, since hormone was no longer being given.