Thirty semen collections (60 ejaculates) from five Nili Ravi Buffalo bulls (6 collections from each bull at weekly intervals) kept at semen production unit Karaniwala, Distt. Bahawalpur were used to study the effect of three extenders (a) sodium citrate; (b) Tris and (c) Lactose-fructose and three freezing programs on the rate of motility and livability of spermatozoa. Hypo-osmotic swelling test (FIOST) and
Eosin-Nigrosin staining were used to estimate sperm livability. The three freezing programs used were; (a) slow freezing, (b) moderate freezing and (c) fast freezing. Differences in the post dilution motility with three extenders i.e. sodium citrate (50.22%), tris (70.67%) and lactose-Iructose (65.83%) were highly significant (P<0.001). The best results in term of motility were observed with tris extender. Post thaw sperm motility was 26.19, 56.50 and 47.37% in sodium citrate, tris and lactose-fructose extenders, respectively and was higher (P <0.05) in tris extender. Post thaw HOST revealed 34.79, 52.38, and 45.64 % HOST-reacted sperm in sodium citrate, tris and lactose-fructose extenders, respectively and was higher (P<0.05) in Iris extender. Sperm motility was higher (P <0.05) in moderate freezing program (46.47%) as compared to slow and fast freezing programmes (42.33% and 41.44%). Similarly, the concentrations of live sperm and HOS-reacted sperm were also higher (P <0.05) in moderate freezing program, whereas non-significant (P>0.05) difference was observed between slow and fast freezing programs. As far as the interaction of extenders and freezing programs is concerned, the semen diluted in the tris extender and frozen by using moderate freezing program exhibited better post thaw semen quality as compared to other extenders and freezing programs used in the study.

CONCLUSIONS AND RECOMMENDATIONS

It was concluded from present study that the quality of Nih Ravi Buffalo bull semen was greatly affected by the type of extenders and freezing programs used in semen processing and freezing.

A combination of tris extender and moderate freezing programme maintained higher motility, livability and integrity of acrosomal membrane of sperm and is therefore recommended for use in artificial insemination programme. The three tests viz; sperm moility, livability and HOST appeared as reliable techniques for evaluation of semen quality.