Motility of bovine spermatozoa extended in "defined" diluents.

Abstract A series of experiments was conducted to develop a "chemically defined" diluent for freezing bovine semen. Egg yolk protein, casein, egg yolk lipoprotein, bovine serum albumin, milk fat triglycerides, egg yolk phospholipids, cholesterol, and egg yolk lecithin were added, individually, in various concentrations, to several buffers as substitutes for milk or egg yolk. Per cent progressive motility of the spermatozoa was the criterion for evaluating the effect of the substitutes, the buffers, and the processing techniques. Sperm motility after freezing and thawing was highest in Tris-buffered diluents containing lipoprotein, phospholipids, or lecithin. Optimum levels of lecithin and phospholipids were 0.34 and 0.65%.