Complementary Milk and Its Relationship to Lactation

Abstract

Cows (62) were used in 1327 trials over a period of 1 year to determine the amount of complementary milk available and its relationship to milk production. Amount of complementary milk available was determined by milking the cows "dry", giving 10 units of oxytocin intravenously, and hand-stripping for complementary milk. The amount of complementary milk varied from 0.1 to 13.3 lbs. with the mean of 1.7 lbs. The percent complementary milk ranged from 1.2 to 70.9% with the mean of 11.3%. Butter-fat percentage of complementary milk ranged from 6.1 to 22.5% with a mean of 13.2%. Use of oxytocin weekly to remove complementary milk had no detectable effect on milk production. The amount of complementary milk decreased with progressing lactation as the amount of yield at normal milking decreased. The percent complementary milk was independent of the stage of lactation, age of the animal, and the amount of yield at normal milking. No relationship was found between persistency of lactation and age of the animal, peak of production, or the trend of butterfat percentage. There was decided negative relationship between persistency and percent complementary milk.