The Effect of Glycerol Level and Rate of Freezing, for Various Extenders, on the Survival of Bovine Spermatozoa Frozen and Stored at −79° C

Abstract

In a study of sperm survival in three different extenders containing three levels of glycerol and frozen at three different rates it was found that a 7% glycerol level resulted in significantly higher survival percentage than either a 10% or 15% level. The 15% level was in no way desirable. A chemical-milk extender, with an average survival percentage of 82.4, was superior to heated homogenized milk or yolk-citrate. A freezing rate of 2.2° C. or 3.3° C. per minute gave significantly higher survival percentages than a rate of 1.1° C. per minute.