Effect of Dietary Fat and Lactation Status on Insulin Binding to Bovine Milk Fat Globule Membranes

Abstract

Lactating cows were used to examine the relationship between lactation status and insulin binding to milk fat globule membranes. Variables evaluated were daily milk yield, stage of lactation, breed, age, lactation number, daily milk fat and protein yields, milk fat and protein percentages, breeding status, body weight, body weight·75, and mammary health. Milk yield was correlated with insulin binding and accounted for 20% of the binding variability. No other variables were related to insulin binding. Insulin binding to milk fat globule membranes increased with supplemental dietary fat up to 4% added fat in the diet dry matter. Milk fat globule membranes may provide a useful model for assessing insulin receptor regulation in the mammary gland. Sources of variation in insulin binding to mammary membranes remain to be identified. © 1987, American Dairy Science Association. All rights reserved.