Evaluation of pregnancy per artificial insemination of dairy animals detected in estrus during the synchronization protocol and assigned to conventional or sexed semen

Anim Reprod Sci. 2023 Aug 30;257:107324. doi: 10.1016/j.anireprosci.2023.107324. Online ahead of print.ABSTRACTThree experiments were designed to evaluate the effects of conventional and sexed-semen on reproductive performance of dairy females detected in estrus. In Exp. 1, 978 lactating Holstein cows and 116 Holstein heifers were used. Cows or heifers were randomly assigned to receive conventional (CONV) or sexed (SEXD) semen on day 0 of a TAI protocol. The TAI was performed using commercial CONV or SEXD frozen-thawed semen from the same 6 Holstein bulls, and SEXD semen was sexed through fluorescence cytometry. In Exp. 2, 390 lactating Holstein × Gir dairy cows and 344 Holstein × Gir heifers were used. Cows and heifers were randomly assigned to receive CONV or SEXD semen on day 0 with frozen-thawed semen from 5 Holstein × Gir bulls. The SEXD was sorted through the Sexcel™ methodology. In Exp. 3, 789 primiparous lactating Holstein cows were enrolled. Cows were randomly assigned to receive CONV or SEXD semen from 5 Holstein bulls, and the SEXD semen was sexed using the same semen allocation methodology described in Exp. 2. All data were analyzed using SAS. Regardless of the experiment, no treatment × bull interaction was observed for any of the variables analyzed herein (P ≥ 0.20). In Exp. 1, multiparous cows assigned to CONV had a greater P/AI vs. cohorts assigned to SEXD (P < 0.01) and a similar response tended to be observed for secundiparous cows (P = 0.10). No ...
Source: Animal Reproduction Science - Category: Zoology Authors: Source Type: research