Experiments on the optimization of the accelerated lambing of three lamb crops in two years in prolific sheep

To establish an accelerated lambing system of three lamb crops in two years in prolific sheep, 404 prolific Suffolk ewes were chosen to carry out the practice of accelerated lambing through taking the measures of estrus synchronization by using the CIDR+PMSG method, artificial insemination and early pregnancy diagnosis by ultrasound. The pregnancy rates of the ewes with intraperitoneal endoscopic insemination and uterine cervical port insemination were compared, the optimal operating procedure was established, and economic benefits were analyzed. The results showed that the estrus rate of ewes with CIDR+PMSG method, abdominal endoscopic insemination, and cervical-oral insemination was 95%, 87%, and 80%, respectively. The proficiency of abdominal endoscopic insemination was superior to cervical-oral insemination. The lambing rate of ewes from the accelerated lambing was 318%, which was 106% higher than once a year lambing（212%）. The cost of estrus synchronization and cervical insemination was 40 yuan per ewe, and economic benefit was 334.04 yuan. It showed that the three lamb crops in two years system can further improve the reproductive efficiency of prolific sheep and increase the economic benefit of lamb farming.