Colostrum is the first drawn milk from the mammary gland after parturition. In composition, colostrum is higher in total solids, protein and ash than normal milk. Usually, a period of 3-5 days postpartum is needed before milk returns to normal composition. The high protein content and solids content is due largely to elevated level of gamma globulin which contains antibodies against various diseases. 3.1 Fat 6.7 4.0 Lactose 2.7 5.0 2.
Pregnancy causes a marked decrease in persistency compared to open cows.
Lactation curves of milk yield and milk fat and protein percentages of Holstein cows. D. Age and size of cow 1. Milk yield increases at a decreasing rate until about the eighth year of age. E. Estrous cycle and pregnancy 1. Pregnancy reduces milk production during concurrent lactation.