Survival of Bovine Spermatozoa Stored at 5 and 25° C. In Extenders Containing Varying Levels of Egg Yolk, Glucose, Glycine, Glycerol, Citrate, and Other Salts

Combinations of 20% egg" yolk with 1.5 to 3.0% solutions of glycinc resulted in poor survival of spermatozoa. Inclusion of 10% glycerol resulted in sperm survival comparable to that obtained in 50% egg yolk-glycine extenders with or without glycerol. A 20% egg yolk extender containing 1.16% sodium citrate dihydrate, 0.75% glycine, and 1.0% glucose was evolved. Twenty ejaculates of semen stored in this extender averaged 41% motile spermatozoa after 12 days of storage at 5 C. Results at 5 C. were superior to those at 25 C. (P < 0.01), even when 0.3% sulfanilamide was added. A yolkcitrate-glucose-glycine-sulfanilamide-antibiotie extender, designated as CU-16, was compared with one designated as CUE, which contained in addition sodium bicarbonate, potassium chloride, and citric acid. In two experiments the percentage of motile spermatozoa over a 12-day storage period at 5 C. in CU-16 averaged 49 and 52, and in CUE averaged 50 and 52 (P > 0.05). The high sperm survival in both of these extenders at 5 C. indicated they might be useful in preserving the fertility of sperm stored for several days at this temperature.