Abstract

Estrus synchronization is an important reproductive management tool in sheep production, as it facilitates controlled breeding and improves reproductive efficiency. This study evaluated two alternative estrus synchronization protocols compared with the conventional controlled internal drug release (CIDR) method in ewes. 24 ewes were randomly assigned to three groups: CIDR for 14 days followed by PMSG, double injections of prostaglandin F2α (PGF2α) followed by PMSG, and a GnRH–PGF2α protocol followed by PMSG. Estrus response, estrus duration, time to estrus onset, pregnancy rate, and conception rate were evaluated. No significant differences were observed among protocols in estrus response or time to estrus onset (P > 0.05). Estrus duration differed significantly (P < 0.05), with the GnRH group showing the longest duration. Pregnancy and conception rates were significantly higher in the CIDR group compared with the other treatments. In conclusion, although CIDR showed superior reproductive performance, alternative protocols such as double PGF2α may represent practical and cost-effective options under field conditions.

Key words: Prostaglandin F2α, GnRH, PMSG, CIDR