Effect of Antibiotics in Extender on Fertility of Liquid Buffalo Bull Semen

This study was carried out to determine if a new antibiotic combination comprising of gentamycin, tylosin and linco-spectin (GTLS) in extender is suitable for improvement in fertility of liquid buffalo bull semen through artificial insemination (AI). Two consecutive ejaculates per week (4 weeks) were collected from three Nili-Ravi buffalo bulls of known fertility by using artificial vagina (42°C). The pooled ejaculates were split-sampled and diluted with skimmed milk extender (37C; 10x10 motile spermatozoa/ml) containing either SP (streptomycin 1000 μg/ml and penicillin 1000 iu/ml) or GTLS (gentamycin 500 μg/ml, tylosin 100 μg/ml, lincomycin 300 μg/ml, and spectinomycin 600 μg/ml). Liquid semen was stored at 5°C for seven days. Fertility test based on 90-days first service pregnancy rate was determined under field conditions. The fertility rates for SP-based vs. GTLS-containing liquid semen of buffalo bull were 58.55 and 60%, respectively, the difference was non significant. The fertility rates also did not differ (P>0.05) due to antibiotics at different days of storage of liquid semen at 5C. In conclusion, GTLS, in skimmed milk extender compared to SP, did not significantly improve the fertility of chilled buffalo bull semen.