Relationship between sperm penetration distance in cervical mucus and frozen semen characteristics vis-à-vis buffalo bull fertility

Abstract

In this study, relationship of sperm penetration distance in mucus was assessed and compared with spermatozoal characteristics, utilizing frozen semen samples obtained from 30 buffalo bulls. Quality semen parameters (motility, kinematics, morphology, viability, HOST, acrosomal and DNA integrity, acrosome reaction) in conjunction with first service conception rate (FSCR) of bulls were determined. Based on penetration distance in buffalo mucus, semen samples were divided into 2 groups, viz. greater penetration distance (GPD, > 20 mm; n, 15) and lesser penetration distance (LPD, < 20 mm; n, 15). Most spermatozoal characteristics were significantly (P<0.05) higher in GPD than in LPD group. The spermatozoa of GPD and LPD were significantly and positively correlated with total motility, progressive motility, acrosome integrity and acrosome reaction. Alternatively, a negative relationship was found with percentage of abnormal spermatozoa and damaged membrane integrity (HOST) in the two penetration distances. In conclusion, significant positive correlations occurred between sperm penetration distance, semen characteristics and fertility parameters. A combination of factors must, therefore, be used to predict the bull fertility. In conclusion, significant positive correlations existed between sperm penetration distance, quality semen characteristics and fertility parameters. The distance penetrated by spermatozoa capable of going beyond 20 mm in an optimized sperm migration test, could be a useful parameter for in vitro evaluation of sperm quality and subsequent fertility of buffalo bulls.