A field study on artificial insemination of swamp and crossbred buffaloes with sexed semen from river buffaloes.

Sex preselection by flow sorting of X- and Y-sperm has been proven to be an efficient and economically feasible strategy for use in Holstein dairy cow breeding, and previous reports have demonstrated the feasibility of altering the sex ratio in buffalo species by using sexed semen in either artificial insemination or IVF. However, because buffalo reproductive physiology and farm management are different from Holsteins, factors involved in artificial insemination by sexed semen need to be further addressed before being applied in buffalo breeding at village-level husbandry. In this study, a total of 4521 swamp or crossbred (F1 or F2) buffaloes with natural estrus were inseminated with X-sorted sperm from river buffaloes, resulting in a 48.5% (2194 of 4521) pregnancy rate and 87.6% (1895 of 2163) sex accuracy in the derived calves. The pregnancy rate obtained with sexed semen from Murrah bulls was higher than that of Nili-Ravi, 52.5% (895 of 1706) versus 46.1% (1299 of 2815; P < 0.01), respectively. Also, significant variations were seen in pregnancy rates from inseminations performed in different seasons (P < 0.01) and by different technicians (P < 0.01). In contrast to Holsteins, no difference was seen in the pregnancy rate between heifers and parous buffalo cows, and buffalo cows with different genetic backgrounds (swamp type, crossbred F1 and F2) showed similar fertility after insemination with sexed semen. The findings in the present study under field conditions pave the way for application of sexing technology to buffalo breeding under village-level husbandry and diverse genetic backgrounds.