Zheng P, Huang H, Li X, Huang F, Adeniran SO, Wang Z, Feng R, Zhang G. LRH-A3 and HCG increase pregnancy rate during timed artificial insemination in dairy cows.
Anim Sci J 2021;
92:e13549. [PMID:
33763962 DOI:
10.1111/asj.13549]
[Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Revised: 02/26/2021] [Accepted: 03/03/2021] [Indexed: 11/30/2022]
Abstract
The objective of this study was to use luteinizing hormone-releasing hormone A3 (LRH-A3) and human chorionic gonadotrophin (HCG) to improve pregnancy rate of dairy cows during timed artificial insemination (TAI). In experiment 1, the TAI process (0 d, GnRH, 100 μg; 7 d, PGF2α, 0.4 mg; 56 hr, GnRH, 100 μg; 16 hr, AI) was applied to 160 dairy cows on 50th and 60th days after parturition respectively. In experiment 2, 320 postpartum dairy cows were treated with TAI (Group A), TAI + 25 μg LRH-A3 (Group B), TAI + 1,500 IU HCG 5 days after AI (Group C), and TAI + 25 μg LRH-A3 + 1,500 IU HCG 5 days after AI (Group D). In experiment 3, endometrial cells were treated with HCG. The results showed that TAI did not affect the pregnancy rate, while LRH-A3 and HCG increased the pregnancy rate of the cow. HCG of 5 IU/ml and 10 IU/ml increased the expressions of leukemia inhibitory factor but decreased those of interleukin-6, epidermal growth factor and vascular endothelial growth factor in endometrial cells. This study provided a plan for the use of LRH-A3 and HCG to increase pregnancy rate during TAI in dairy cows.
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