The Effects of Hourly Milking with the Aid of Intravenous Injections of Oxytocin

Abstract

Four cows were milked hourly up to 156 consecutive hours with intravenous administration of oxvtocin at each milking. The average butterfat percentage and butterfat and milk yields were above the pre-experimental levels considering the entire experimental period. During the initial 4 hours the butterfat percentage dropped from the peak at 1st hour to below the average of pre-experimental level. Then it rose from a below normal level in the early part to significantly above normal as the experiment progressed. There was a great deal of variation from hour to hour in fat percentage and saponification numbers, as well as in N partition and lactose content. It appears that milk constituents are relatively independently formed in, or transported to the lumen of the alveoli. Composition of milk collected after greater time interval between milkings is more constant, because the hourly random variability is averaged out.