Comparative efficacy of skimmed cow milk and soymilk based extenders on sperm viability for cryopreservation of bull semen

Abstract

Maintaining a successful artificial insemination program depends on a number of factors, including evaluation of semen characteristics. The quality of preserved semen depends on several factors but dilution of sperms in a suitable extender is one of the important factors affecting sperm survival during preservation. Components of animal origin may also present a potential microbiological risk compromising the quality of preserved semen and standardization. This study compared the efficacy of soya milk and skimmed milk based extenders on the sperm motility and live sperm concentration of bull semen at different storage conditions before and after cryopreservation in liquid nitrogen. This could be an alternative to replace the components of animal's origin in semen extenders. During this study, semen samples were collected from 3 mature healthy exotic bulls within a reproductive age and having proper nutrition using an artificial vagina and analysis done using computer aided semen analysis (CASA). The semen samples were diluted using the two extenders and then kept in the fridge at 4oC for 2 hours before packaging. Refrigerated semen was also evaluated for the above parameters before cryopreservation. Overall, percent motility was relatively higher for all the study bulls (above 70%). All the samples exhibited a live percentage of over 80% immediately after collection. In the present study, satisfactory sperm quality parameters were sustained in semen diluted with both extenders for the study period, immediately after refrigeration, freezing and cryopreservation with relatively better results in soya milk extender compared to skimmed milk. The results of statistical analysis revealed that there was no statistically significant difference between the efficacy of soya milk and skimmed milk extenders (p<0.05). There was also no difference in the semen parameters when observed over the period of four days