Freezing Point of Artificially Induced Bovine Mammary Secretions

Abstract

IT is well known that the freezing point depression of milk is remarkably constant for cows in normal lactation¹. Folley and Malpress² have described experiments in which maiden Shorthorn heifers were treated by implantation of diethylstilbœstrol and hexœstrol, and they were good enough to supply me with samples of secretions from one animal in the former and two in the latter experiment. Three control animals from the same herd were also tested. Lactation in the three virgin heifers was initiated on May 21, 1942, following the administration of hormones on May 11, 1942. One heifer received, during the treatment, 2.40 gm. of diethylstilbœstrol, the second and third, 5·01 gm. and 2·54 gm. of hexœstrol tablets. The heifers were milked once a day until they yielded 5 lb. of milk, when they were milked twice a day. The maximum daily yield was 22 lb. from one heifer and 17 lb. and 14 lb. from the others.