Study On The Changes Of Reproductive Hormones And Early Pregnancy Monitoring In The Breeding Period Of Dolang Sheep

Dolang sheep is a very good sheep breeds in Xinjiang,which has plenty of stable genetic traits such as both meat and fat,large body size,fast weight gain,high reproductive rate,high double lamb parturition rate,high meat production rate,good and much hair,gentle temperament,stress resistance and disease resistance.The sheep is mainly distributed in some areas of Yeerqiang river basin at the southeast edge of the Taklimakan Desert.In the sheep breeding industry,the reproductive efficiency is one of the important factors affecting the efficiency of sheep breeding.And improving the breeding frequency and lambing rate is the common pursuit of the majority of farmers.Therefore,it's of great significance to the development of animal husbandry in southern Xinjiang to further explore its reproductive potential.Test 1:In this experiment,eight healthy Dolang sheep were selected,which had given birth to a second litter.CIDR+PMSG+PG method was used for estrus synchronization,and rutting sheep were mated.The concentrations of major reproductive hormones in the blood during estrus and pregnancy were measured by ELISA kit,and the experimental data were analyzed by SPSS.The results showed that CIDR+PMSG+PG method could increase the estrus rate of Dolang sheep to87.5%and the conception rate to 100%.During the estrus cycle,the difference in the change of concentration of FSH was not significant,the concentration in pre-rut was higher,and then gradually decreased to a steady level.the difference in the change of concentration of FSH was also not significant,the concentration was higher at the day before estrus,and the concentration was lower in the middle estrus.The concentration of E₂ increased at the day before the onset of estrus,peaked on the day of estrus,and decreased to a stable level after the end of estrus.The change of LH showed pulsatile secretion in the estrus cycle and reached its peak at the day before estrus.During gestation,P₄,E₂ and LH concentrations all fluctuated to some extent,but there was no significant difference in their variation rules,and the variation rules were basically the same.The concentrations of E₂ and LH both increased during gestation,while the concentrations of P₄ had a downtrend.Test 2:The experimental sheep in text 1 were used.The development situation of ovaries and follicles during estrus were observed with B-ultrasound as well as the development situation of fetus during the early pregnancy.The results showed that the diameter of the ovary during estrus was about 12.3mm.During estrus,the diameter of the ovary was about 25.9mm,and the diameter of the follicle was about 10mm.On the 19th day of gestation,the uterine lobule of"copper coin"can be clearly seen under the ultrasound image,confirming that the ewe has entered the gestation period.Above results provide reliable theoretical data for estrus and pregnancy identification of ewes in the breeding industry,so as to reduce the empty pregnancy rate of ewes and greatly improve the benefits of the breeding industry.