非繁殖季节母驴诱导发情、排卵效果的研究

目的]研究前列腺素F2α（PGF2α）、孕马血清促性腺激素（PMSG）、人绒毛膜促性腺激素（hCG）3种激素在不同处理方案下对内蒙古通辽地区乏情期母驴卵泡生长情况、排卵率、发情率、受胎率与妊娠率的影响。方法]将50头2～6岁、体重接近、体况良好、处于乏情期的母驴随机分为A、B、C、D4组，其中D组为未使用任何激素的空白对照组。首先，采用PGF2α、PMSG进行诱导发情试验，对A、B、C3组母驴注射2mL／头PGF2α,连续处理5d，第6天对A、B组母驴分别注射PMSG 1000IU，头和500IU，头；C组不做PMSG处理。诱导发情后将A、B组再细分为A1、A2和B1、B2组，当A1、B1、C3组中母驴卵泡直径大于35mm时注射hCG（总量1500IU）进行诱导排卵；A2、B2不做hCG处理，由卵泡自然发育至排卵。对所有诱导发情后有发情表现的母驴进行自然本交。同时，在试验期间利用直肠检查和B超检查对母驴的卵巢发育进行监测。『结果]c组发情率为30％，经PGF2α处理第5天时卵巢黄体基本全部消退；A组和B组的发情率分别为93．33％和86．66％，二者差异不大，但均明显高于C组。A1、B1最终的排卵率为100％和77．78％，而A2和B2的排卵率为60．00％和50．00％。A，组受胎率和妊娠率最高，分别达到了88．89％和80．00％，其次是B，组分别为66．67％和60．00％，B2、C2组的受胎率和妊娠率都较低，D组虽然有1头母驴发情，但配种后未妊娠。结论]单独使用PGF2α对非繁殖季节母驴诱导发情效果不明显，但其对消除母驴黄体有明显作用；PGF2α与PMSG联用对诱导乏情母驴发情效果较好。使用PGF2α与PMSG对处于乏情期的母驴诱导发情后，注射hCG对母驴卵巢上优势卵泡具有明显的促进排卵作用，能加快优势卵泡的排卵，且明显提高母驴的排卵率。该试验确定的最佳方案为：注射0．2mgPGF2α连续处理5d，第6天注射PMSG 500lU，当优势卵泡直径达35mm时注射hCG 1500lU，排卵后配种。

Effect of Hormone-induced Estrus and Ovulation in Female Donkey during Non-breeding Season

Objective]To assess the effect of PGF2α, PMSG and hCG with different treatment protocols on follicular growth, ovulation rate, estrus rate, conception rate and pregnancy rate of female donkeys selected from Tongliao region of Inner Mongolia during the seasonal anestrus. Methods] A total of fifty healthy female donkeys 2-6 years of age in seasonal anestrus were randomly divided into four groups （A, B, C and D）. A hormone-induced estrus experiment with administration of PGF2α in combination with PMSG was carried out： the donkeys in groups of A, B and C were injected with 2 mL PGF2α for five consecutive days; those in group A or group B were subsequently administrated with 1 000 IU or 500 IU PMSG at the sixth day, respectively; group C received no PMSG treatment. After the hormone-induced estrus, the group A and group B were randomly allocated to groups of A1, A2 and groups of B1, B2, respectively, to perform the ovulation induction experiment： the donkeys in groups of A1, B1 and C received hCG injection （total dosage 1 500 I U） when their follicular diameters were larger than 35 mm; those in groups of A2 and B2 received no hCG treatment, and their follicles naturally developed until ovulation. The donkeys exhibiting estrous appearance were subjected to natural mating. Meanwhile, the ovarian development of the donkeys was monitored by using rectal examination and B-type ultrasound examination during the experimental period. Group D served as a control of non-hormone treatment. EResultslThe estrus rate of group C was 30% and the ovarian corpus luteum was completely regressed at the fifth day of PGF2α treatment; while there was no obvious difference in estrus rate between group A （93.33% ） and group B （86.66%）, both of them were obviously higher than group C. The ovulation rate of groups of A1, B1, A2 and B2 was 100%, 77.78%, 60.00% and 50.00%, respectively. The highest conception rate （88.89%） and pregnancy rate （80.00%） were both observed in group A1 followed by group B1（66.67% and 60.00%, respectively）. Groups of B2 and C had lower conception rate and pregnancy rate. While there was one donkey had estrous appearance in group D, no pregnancy was observed after mating. Conclusion]Although single treatment of PGF2α had no obvious estrus-inducing effect on female donkey during non-breeding season, it had obvious effect on corpus luteum regression; the combinative treatment of PGF2α and PMSG showed satisfied estrus-inducing effect. After estrus induced by PGF2α in combination with PMSG, injection of hCG accelerated the ovulation of the dominant follicles in ovary of the female donkeys and thus elevated the ovulation rate. The optimized treatment protocol of hormone-induced estrus and ovulation for female donkey during non-breeding season was as follows： （1） injection of 2 mL PGF2α for five consecutive days, （2） administration of 500 IU PMSG at the sixth day, （3） injection of 1 500 IU hCG when the diameter of dominant follicles reached 35 mm,（4） natural mating after ovulation.