Use of Mechanical Refrigeration in Preservation of Bull Semen

Abstract

Quality of frozen bovine semen (as determined by percentage of live cells and progressive motility) was compared for 12 split ejaculates after storage for periods as long as 24 weeks under 2 temperature conditions. Forty ampules of each ejaculate were stored under dry ice refrigeration (-72.6[degree]C) and mechanical refrigeration (Sub-Zero Products Co., Cincinnati, Ohio) at -96[degree]C, Transfers of ampules to the opposite storage condition were made at various intervals. Microscopic evaluation of the samples indicated that the quality of semen was maintained better under mechanical refrigeration, and that samples could be transferred from one storage condition to the other without decreasing the quality of the semen below that maintained under dry ice refrigeration.