| Xinjiang is a large province of donkey breeding in China,donkey breeding is mostly distributed in Kashgar,Hotan and other areas in southern Xinjiang,and small-scale free-range rearing and natural mating are often used in production.Due to its unique physiological characteristics(A donkey’s ovarian cortex is inside and the medulla is outside),donkeys have a long period of estrus and scattered ovulation time,which not only increases the difficulty of the application of modern breeding technology,but also affects the expansion speed of fine breeds and the transformation of the donkey industry.In order to study the development of follicles in donkeys during estrus,observe the difference between natural ovulation and hormone induced ovulation and the influence of hormone induction on the fetal rate,this experiment had randomly selected 90 estrus female donkeys in spring and autumn,and had divided them into spring control group,spring H group,spring G group,autumn control group,autumn H group and autumn G group.When the follicles of the experimental group H and G had been greater than 30 mm in diameter,h CG(2000 IU)and Gn RH(100 μg)had been injected respectively to observe the effect of hormone induction in different seasons,and to artificially inseminate the female donkey in a timely manner to analyze the effect of hormone induction on the fetal rate of the female donkey.The results show:(1)The diameters of the dominant follicles of female donkeys in estrus in spring and autumn were 30.53±4.07 mm and 31.16±3.18 mm,respectively.The average diameter of follicles in estrus in autumn was higher than that in spring.;(2)The ovulation rate of the spring control group,spring H group and spring G group were33.3%,93.3% and 100% within 48 h,respectively,and the ovulation rate of the autumn control group,autumn H group and autumn G group were 13.3%,60% and 80% at 48 h respectively.The control group used to ovulation longer than in the hormone-treated test group,and the autumn hormone-treated group used to ovulate longer than in the spring hormone-treated group;(3)The sequence of average growth rate of follicles before ovulation in spring and autumn from high to low was control group,G group,H group,and the difference between H group and control group and G group in the two seasons was significant(P-value less than 0.05),and the growth rate of follicles in each group had decreased compared with spring.(4)The diameter of the hormone-treated test group in spring and autumn had been smaller than that of the control group 24 h before ovulation,and the sequence from high to low was control group,G group,H group.There had been significant differences between the spring control group,spring G group and spring H group(P-value less than 0.05),and the autumn control group was significantly different from the autumn G group and the autumn H group(P-value less than0.05).(5)The sequence of spring conception rate from high to low was spring G group,spring H group,spring control group,which were 86.7%,66.7%,and 40%,respectively.And the sequence of the conception rate in autumn from high to low was the autumn group H(60%),the autumn G group(53.3%),the autumn control group(46.7%).The fertilization rate of artificial insemination after hormone-induced ovulation had been higher than that of the control group,and the conception rate of the hormone-treated group in autumn had decreased compared with that in the spring.In summary,whether in spring or autumn,Gn RH and h CG can promote the development and ovulation of the dominant follicles of the female donkey and improve the fertility rate,of which Gn RH induces ovulation earlier than h CG. |
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