Hormonal Induction of Lactation in the Bovine: Mammary Gland Histology and Milk Composition

Abstract

Mammary gland histology and milk composition were studied in Holstein cows and heifers induced to lactate following 17fi-estradiol and progesterone therapy for 7 days. The mostnotable gross histological observation was a large number of immature or developing duets and alveoli. These ducts and alveoli were without lumen and consisted mainly of clumped columnar epithelial cells. No gross histological abnormalities were seen. The composition of milk from induced lactations with regard to fat, protein, and lactose percentages was not significantly different from milk from lactations following parturition during the first 21 days of lactation.