Picard-Hagen N, Lhermie G, Florentin S, Merle D, Frein P, Gayrard V
Université de Toulouse, Institut National Polytechnique de Toulouse, École Nationale Vétérinaire de Toulouse, Toulouse, France; INRA, UMR 1331 Toxalim, Research Centre in Food Toxicology, Toulouse, France.
Vetoquinol France, Paris, France.
Theriogenology. 2015 Jul 15;84(2):177-83. doi: 10.1016/j.theriogenology.2015.03.004. Epub 2015 Mar 14.
Analogs of gonadoliberin (GnRH) are widely used in cattle to synchronize estrus and to induce ovulation, as well as for the treatment of ovarian cysts. The aim of this study was to compare the plasma profiles of LH and progesterone and the follicular dynamics in response to the administration of gonadorelin, lecirelin, or buserelin at the dose recommended to induce ovulation. In addition, the biological response to a half dose of lecirelin was assessed. Twelve healthy Holstein female cows were divided into four sequence groups, according to a Latin square design and received the four treatments during the four periods of the study. Before each period, the estrous cycle was synchronized, and on Day 6 or 7 of the ensuing cycle, the time at which it was most likely to have a dominant follicle, 100 μg of gonadorelin, 25 μg of lecirelin, 50 μg of lecirelin, or 10 μg of buserelin was administered to the cows. Blood samples were regularly collected for up to 4 days after the GnRH administrations. The plasma LH response was evaluated for up to 6 hours after administration, and the plasma progesterone response and ovarian follicular dynamics were evaluated for up to 4 days. There was a significantly lower LH release after gonadorelin treatment compared to lecirelin at the doses of 25 or 50 μg and the buserelin treatment. The mean maximal LH concentration after gonadorelin treatment was 2.5 lower than after lecirelin or buserelin treatment and was reached 1 hour earlier. Four days after the GnRH administration (i.e., at Days 10-11 of the estrous cycle), the overall mean increase in plasma progesterone concentration was 70% and did not differ between the treatment groups. The percentage of disappearance of the dominant follicle (84.8% of ovulation and 4.3% of luteinization) after GnRH treatment was high (73%, 82%, 100%, and 100%, for gonadorelin, lecirelin at the doses of 25 and 50 μg, and buserelin, respectively) and did not differ between the GnRH treatments. The follicle disappearance was followed by the emergence of a synchronous follicle wave within 2 days in almost all the heifers. Altogether, our data show that the three GnRH analogs, at the doses indicated for the induction of ovulation or at a half dose for lecirelin, are almost equally effective to induce the disappearance of the dominant follicle at Day 6 to 7 of the estrous cycle.
促性腺激素释放激素（GnRH）类似物在牛中被广泛用于同步发情、诱导排卵以及治疗卵巢囊肿。本研究的目的是比较在推荐诱导排卵剂量下，给予戈那瑞林、来舍瑞林或布舍瑞林后，血浆促黄体生成素（LH）和孕酮水平以及卵泡动态变化。此外，还评估了半剂量来舍瑞林的生物学反应。根据拉丁方设计，将12头健康的荷斯坦母牛分为4个序列组，并在研究的4个阶段接受这4种处理。在每个阶段之前，使发情周期同步化，在随后周期的第6天或第7天，即最有可能出现优势卵泡的时间，给母牛注射100μg戈那瑞林、25μg来舍瑞林、50μg来舍瑞林或10μg布舍瑞林。在给予GnRH后定期采集血样，持续4天。给药后6小时内评估血浆LH反应，给药后4天内评估血浆孕酮反应和卵巢卵泡动态变化。与25μg或50μg剂量的来舍瑞林以及布舍瑞林处理相比，戈那瑞林处理后LH释放显著降低。戈那瑞林处理后的平均最大LH浓度比来舍瑞林或布舍瑞林处理低2.5倍，且提前1小时达到峰值。在给予GnRH后4天（即发情周期的第10 - 11天），血浆孕酮浓度的总体平均升高为70%，各处理组之间无差异。GnRH处理后优势卵泡消失的百分比（排卵占84.8%，黄体化占4.3%）很高（戈那瑞林、25μg和50μg剂量的来舍瑞林以及布舍瑞林分别为73%、82%、100%和100%），不同GnRH处理之间无差异。几乎所有小母牛在卵泡消失后2天内会出现同步卵泡波。总之，我们的数据表明，这三种GnRH类似物，在用于诱导排卵的剂量下或来舍瑞林的半剂量下，在发情周期的第6至7天诱导优势卵泡消失的效果几乎相同。
