Diluters for Bovine Semen. IV. Fertility of Bovine Spermatozoa in Heated Homogenized Milk and Skimmilk

Abstract

Fresh heated homogenized milk and fresh heated skim milk can be used as practical diluting fluids for bull semen based on the results of 2 split sample fertility experiments. Standard egg yolk-citrate diluter served as the control diluter and penicillin and streptomycin were routinely added to all diluters. In the 1st trial, 105 semen samples from 7 Holstein bulls of high fertility were used to inseminate 4689 cows. The average 60- to 90-day nonreturn rate was 76.1% for heated homogenized milk, 74.3% for heated homogenized milk plus 1% cornstarch, and 75.9% for egg yolk-citrate. The addition of cornstarch to increase the viscosity of milk diluter did not improve fertility and was found to be unnecessary. In the 2d experiment, heated homogenized milk and heated pasteurized skim milk (both containing 1% cornstarch) were compared with egg yolk-citrate. Based on inseminations to 8399 cows with 72 ejaculates from 8 bulls of average or above average fertility, the nonreturn rate was 65.3% for heated homogenized milk, 67.8% for heated skim milk, and 66.8% for yolk-citrate. The differences among diluters were not statistically significant in either experiment.