IntroductionFreezing of semen in a suitable extender has opened a new vista in artificial insemination. It induces temporary quiescence in spermatozoa which can be stored for later resuscitation. Extensive data have shown that bovine spermatozoa can survive freeze-thawing when extended in glycerol-containing media (PICKETT and BERNDTSON, 1974;FOOTE, 1970). In contrast, limited success has been achieved in freezing buffalo semen (BHATTACHARYA and MAULE, 1962; BHOSREKAR, 1974), using the conventional egg-yolk citrate (EYC) diluent employed for bull semen; it is less effective for buffalo semen preservation. A new diluent, citric acid whey (CAW), has been recently evolved for buffalo semen preservation and freezing in this laboratory (GAN- GULI et al., 1973; GANGULI, 1974). The extracellular release of transaminase (CHINNAIYA et al., 1979) and the uptake of labelled glucose and fructose by buffalo spermatozoa in extenders during cold storage (ATREJA and GANGULI, 1978) have been reported. In the light of these observations, an assessment of the acrosomal damage in relation to leakage of acrosin of buffalo spermatozoa during freezing has been made when semen was extended in different media containing glycerol. This report presents results that indicate an almost similar efficiency of three diluents tested for freezing buffalo semen, as revealed by the acrosomal characteristics.
Material and MethodsSemen samples were collected once a week from Murrah buffalo bulls using the artificial vagina technique (WALTON, 1945), two successive ejaculates being collected at a time. Semen quality was evaluated by the method of HERMAN and MADDEN (1953). Samples having high initial motility, with a score between 3.5 and 4.5 (5 being the best motility), determined microscopically, were split into three equal parts and diluted with CAW, EYC and Tris-'*