Effect of duration of progesterone-releasing device (controlled internal drug-release insert) treatment on reproductive performance in beef cows

Le résumé fourni par la source

The objective of this experiment was to determine the effect of reducing the duration of progesterone-releasing device (CIDR) treatment, in a CIDR-based timed AI synchronization protocol [CIDR-prostaglandin F2α (PGF2α)– gonadotropin-releasing hormone (GnRH) and AI], on AI pregnancy rate (P/AI) and overall pregnancy rates in primiparous and multiparous, suckled beef cows. British crossbred cows (n = 138) were paired by parity, days postpartum (DPP), age, and BW and were assigned to one of 2 treatments: 1) cows (n = 68) received a CIDR (d -7) for 7 d, PGF2α (25 mg) at CIDR removal (d 0), GnRH (75 μg) 56 h after CIDR removal, and immediate AI on d 3 (CIDR7) or 2) cows (n = 70) received a CIDR (d -5) for 5 d, PGF2α at CIDR removal (d 0), GnRH 56 h after CIDR removal, and immediate AI on d 3 (CIDR5). All cows received AI by a single inseminator. Cows were exposed to bulls 15 d after timed AI. Pregnancy status was determined by ultrasonography 32 and 70 d after AI. Treatment had no effect on P/AI (54.4 and 57.1% for CIDR7 and CIDR5, respectively). Overall pregnancy rate was also unaffected by treatment protocol (79.4 and 77.1% for CIDR7 and CIDR5, respectively). Age, BW, and BCS did not have an effect on P/AI and overall pregnancy rate. Days postpartum had a significant effect (P 60 DPP) and overall pregnancy rate (50% for 60 DPP). Results indicate that reducing the duration of CIDR treatment from 7 to 5 d in a CIDR-based timed AI protocol did not influence P/AI and overall pregnancy rate in suckled beef cows.

Ce résumé expose les affirmations des auteurs. BNTIC ne l’interprète pas comme une validation indépendante des résultats.