Glycerolation and Thawing Effects on Bull Spermatozoa Frozen in Detergent-Treated Egg Yolk and Whole Egg Extenders

Bull sperm in Experiment 1 were added to a standard egg yolk-Tris extender containing 0, .25, .5, 1.0, 1.5, and 2.0% (vol/vol) of the detergent mixture, sodium and triethanolamine lauryl sulfate. Glycerol was added in one step to the initial extender or in three steps after cooling semen to 4 degrees C. The extended semen was packaged in .5-ml French straws and frozen over static nitrogen vapor. Thawing was at 4, 30, and 60 degrees C. There was little difference due to the method of adding glycerol provided detergent was present. Percentages of motile sperm after freezing in the six concentrations of detergent, in ascending order, were 31, 45, 52, 51, 48, and 36. Percentages of motile sperm following thawing at 4, 30, and 60 degrees C were 36.5, 46.0, and 48.6. Acrosome retention also was better preserved with the higher thaw temperatures. A second experiment, similar in design to the first one, was conducted with whole egg-Tris extender. The best results were in whole egg-Tris containing .125% detergent where post-thaw motile sperm of 70.4% greatly exceeded 30.7% without sodium and triethanolamine lauryl sulfate. Fertility of sperm frozen in yolk-Tris-detergent was equivalent to whole milk used as a control.