The Use of Dimethyl Sulphoxide, Glycerol, and Reconstituted Skim Milk for the Preservation of Ram Spermatozoa II. The Influence of Diluent Composition and Processing Time During Freezing to ?79°C with Dimethyl Sulphoxide or Glycerol or Both Compounds

Abstract

Reconstituted skim milk diluents containing dimethyl sulphoxide or glycerol or both substances were used to deep-freeze ra.m spermatozoa to -79°C. Very poor revival (less than 10%) followed freezing in dimethyl sulphoxide. Small improvements in revival were obtained by adding 2% (w/v) fructose to the diluent and shortening the equilibration time to 10 min before freezing. The inclusion of 1 . 5 % (v/v) dimethyl sulphoxide in a diluent containing 7% (vjv) glycerol improved revival.