Studies on bacterial load in bovine and bubaline semen of breeding bulls in Karnataka

Indian dairying has emerged as the world's largest producer of milk and this was possible to a greater extent with the introduction of artificial insemination (AI) and frozen semen technology. India has around 64 frozen semen bull stations and more than 60,000 AI centers. However, bacterial contamination has played a significant role in downgrading the quality of semen. Hence, in the present study an attempt has been made to estimate the level of bacterial load in neat semen, extender and frozen semen straw in three different breeding farms/semen collection centers of Karnataka. A total of twenty-eight HF bulls (Farm A - 08, Farm B - 12 and Farm C - 08) and fourteen Murrah (Farm A and C), two Surthi (Farm C) buffaloes were selected for the study. The bacterial load is more in neat semen compared to the frozen semen straws due to the usage of antimicrobials during the semen straw processing. In all the three farms, the extender didn't show growth of any bacteria, indicating that it has been prepared aseptically and not contributing to any bacterial load. The mean bacterial load (CFU) is more in Farm C compared to the Farm A and B. It can be mainly attributed to the greater number of animals involved in collection per day in that farm compared to the other two. Hence, more exposure to the inevitable contaminants and delay in processing might have contributed to it. There is significant variation (P<0.05) in the overall mean values (HF and Bubaline) observed between the Farm A and Farm C both in neat and frozen semen. However, no significant variation (P>0.05) between the collections in all the three farms, clearly indicates the repetition of the same standard operation procedure in all the farms during the collections.