Estrus synchronization schemes and application efficacies in anestrus lanzhou fat-tailed ewes

Abstract

This study aims to investigate the estrus efficacy of FIS (fluorogestone intravaginal sponges)/eCG (equine chorionic gonadotropin) and cloprostenol treatments to establish the optimum protocols for estrus synchronization in ewes. Forty-two ewes were assigned into groups A (FIS/eCG group) and B (CLO (cloprostenol) group). Each group was randomly divided into three subgroups (n = 7) according to the dose of eCG (ECG1, ECG2 and ECG3) or cloprostenol (CLO1, CLO2 and CLO3). The estrus rates, lambing rates and average litter sizes were accounted. Serum concentrations of progesterone (P4), follicle-stimulating hormone (FSH) and luteinizing hormone were determined. Selected optimum schemes were employed in 636 ewes in four sheep farms. Estrus rates of groups A and B were 85.72% and 57.14%. Estrus onset times (EOTs) were 53.91 ± 12.26 and 46.41 ± 4.65 h for groups A and B. EOT of ECG1 was longer than that of CLO3 (P