Effect of egg yolk lipids on the freezing of goat semen

Jamunapari goat buck semen contained both phospholipase and lysophospholipase activities which remained active during dilution (Step I) with diluents containing egg yolk, cooling to 5 degrees C (Step II), glycerolization and equilibration (Step III) and freezing and thawing (Step IV). A quantitative estimate of the phosphatidyl choline and phosphatidyl ethanolamine before and after freezing revealed that the lipids in egg yolk added to dilute goat semen were not hydrolysed to lysophospholipids and free fatty acids. Seminal plasma was, therefore, not removed and goat semen was frozen in egg yolk citrate-glucose, egg yolk-tris and skim milk-egg yolk. Dilution of goat semen 20 times with the three extenders containing 7% glycerol and an equilibration time of 3 h yielded optimum results. A comparative evaluation of freezing in the three diluents based on the assessment of sperm motility, live sperm count and acrosomal damage showed egg yolk-tris to be best extender for the successful freezing of goat semen. Insemination trials conducted with frozen semen and the number of actual kiddings yielded a fertility rate of approximately 81% in our study.