Post artificial insemination conception rate of a Brahman bull in selected areas of Bangladesh

Abstract

Background: To mitigate the increasing protein demand in Bangladesh, recently the government has started a program to inspire the farmers for rearing Brahman as a beef breed. But, it is necessary to assess the performance of frozen semen of Brahman bull and the other factors that affect the rate of conception after Artificial Insemination (AI) before widespread rearing in Bangladesh. Methods: Data on AI performance, different factors and rate of conception were collected from 150 inseminated cows and heifers of Sadar upazila, Mymensingh. The cows were inseminated by trained technician of Research Animal Farm of Department of Surgery and Obstetrics, BAU, Mymensingh. Results: The overall conception rate was 55.3%. The conception rate in Holstein Friesian cross (68.9%) and Sahiwal cross (66.7%) cows were relatively higher than that of Local (46%) cows. Upon increasing age the service required for conception was irregular. The conception rate with respect to different parities ranged from 47.0% to 58.7%. Cows received insemination at parity 1-2 showed highest conception rate (60.0%) and cows received insemination at parity 3-7 showed lowest conception rate (47.0%). There was no significant difference between them on conception rate. The conception rate was observed higher (69.2%) in the cows which were inseminated in spring than cows were inseminated in summer (57.3%), winter (53.3%) and rainy (38.5%). The pregnancy rate in cows having BCS 2.5-3 was higher (60.7%) than that of 2.0 and 3.5-4.0. However, the difference in conception rate did not vary significantly among different BCS of cows (p>0.05). The present study indicated that the pregnancy rate in cows was higher (76.9%) that yield 6-10 L of milk than those of 0, 1-2 and 3-5 L counterpart. However, the variation in conception rate with different milk yield was significant (p<0.05). The pregnancy rate in cows that inseminated between 19-24 hours was higher (66.0%) than that of ≤12 and 13-18 hours. The variation in conception rate with different interval between estrus to AI was significant (P<0.05). Conclusion: Further studies using more population of cows and semen donors are needed to confirm this result as low number of cows and only one semen donor were used in this study.