S.M.H. Andrabi, N. Ahmad, A. Abbas and M. Anzar

Abstract   

    This study was carried out to identify the suitable antibiotic combinations in semen extender for improvement in fertility of frozen semen of buffalo and cow (Sahiwal) bulls to obtain better pregnancy rate through artificial insemination (AI). For this study eight first ejaculates, four each from a buffalo and a cow (Sahiwal) bull were used. The ejaculates were split-sampled and diluted with Tris-citric acid extender (at 37°C; 50x 106 spermatozoa/mI), containing either SP (streptomycin 1000 ~g/ml and penicillin 1000 IU/ml) or GTLS (gentamycin 500 µg/ml, Tylosin 100 µg/ml and linco-spectin 300/600 µg/ml). There was no difference in post-thaw motility for these samples. Fertility test based on 75-days first service pregnancy rate was determined under field conditions. A total of 400 inseminations were recorded, 200 for each buffalo and cow (Sahiwal) with J 00 of each antibiotic combination, respectively. Fertility rates for SP-based frozen semen of buffalo bull were 41.66% and were 55.2% for GTLS-containing frozen semen, respectively. The results for GTLS were higher (P<0.0001) than SP. Similarly, fertility rates were higher (P<0.0001) for GTLS-based frozen semen of Sahiwal bull (78.78%) than SP-containing frozen semen (69.6%) of the same specie. Fertility rates also differed due to species of donor bulls. They were better (P<0.0001 ) for the frozen Sahiwal bull semen than that of the buffalo bull in both SP and GTLS- based frozen semen samples, respectively. In conclusion. seminal quality measured by field fertility trial indicated GTLS combination of antibiotics added to the semen extender was better for improvement in the fertility of frozen buffalo) and Sahiwal bull semen, by yielding better pregnancy rates through AI

Key words: antibiotic combination, frozen semen, fertility, buffalo, Sahiwal.