Comparison of an oestrus synchronisation protocol with oestradiol benzoate and PGF2α and insemination at detected oestrus to a timed insemination protocol (Ovsynch) on reproductive performance of lactating dairy cows
نویسنده
چکیده
A total of 226 out of 245 postpartum lactating dairy cows in a commercial dairy farm were allocated to two groups of oestrous synchronisation protocols in order to evaluate reproductive performance. One group was treated with oestradiol benzoate (ODB) and PGF2α on day 10 of the oestrous cycle with insemination at the detected oestrus, the second group underwent the Ovsynch (OVS) protocol (GnRH + PGF2α + GnRH) with timed AI. Pregnancy was diagnosed by ultrasonography on day 28 after AI and confirmed by rectal palpation on day 45. A higher (P < 0.001) proportion of cows in OVS (100%) were inseminated within (19.2 ± 3.8 h) following the second GnRH injection than those of cows in EPE (ODB + PGF2α + ODB) (70.6%) inseminated at the detected oestrus within (35.6 ± 5.2 h) following the second ODB injection. Pregnancy rates for the first AI at day 28 (64.0 ± 4.6, 62.4 ± 5.5%) and at day 45 post-insemination (40.4 ± 4.7, 40.0 ± 5.6%) for OVS and EPE cows respectively, did not differ between the two treatments, whereas, the overall pregnancy rates tended to be higher (P < 0.08) for the OVS (85.1 ± 3.8%) cows than the EPE cows (74.1 ± 4.5%). No differences were observed in pregnancy rates for first AI and overall up to fourth AI between primiparous (34.7 ± 5.8 and 85.3 ± 4.7%) and multiparous cows (43.5 ± 4.5 and 77.4 ± 3.6%). Days open for pregnant cows tended to be lower (P < 0.08) for OVS (76.2 ± 3) than for EPE cows (84.7 ± 4), while days open were higher (P < 0.05) in primiparous cows (85.3 ± 4) than in multiparous cows (75.6 ± 3). The results indicate that pregnancy rates for first AI were similar, but overall pregnancy rates up to the fourth AI tended to be higher for OVS than EPE cows, while days open was tended to be lower for OVS than EPE cows. dairy cows / oestrus-synchronisation / GnRH / oestradiol / PG / reproductive performance
منابع مشابه
Synchronisation of ovulation for management of reproduction in dairy cows.
Important developments have occurred in the last two decades, since the advent of the Ovsynch protocol, on the understanding and use of synchronisation programmes for management of reproduction in dairy herds. This better understanding of oestrus cycle control associated with suboptimal reproductive performance in dairy herds has led dairy producers to quickly adopt timed artificial inseminatio...
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