Effects of Composition of Diluent, Method of Addition of Glycerol, Freezing Rate, and Storage Temperature on the Revival of Ram Spermatozoa After Deep-Freezing

Abstract

The addition of 6% (vJv) egg yolk to a synthetic diluent [247 mM glucose, 49 mM NaCI, 5 mM KCI, 5 mM phosphate buffer, and 7·5% (vJv) glycerol] improved the survival of ram spermatozoa after deep·freezing. Judging by the activity of spermatozoa after thawing, a single addition of glycerol to the diluted semen at 5°C was as effective as multiple additions giving a graded increase of glycerol concentra-tion over a period of 20 min. Reciprocal replacement of the sodium chloride of the diluent by an increase in the concentration of the phosphate buffer showed that motility of the spermatozoa after thawing was depressed when the level of phosphate exceeded 10 mM.