Comparison between Day 0 and traditional protocols for estrus synchronization and multiple ovulation in crossbred hair sheep

This study was carried out to compare Day 0 and traditional protocols for in vivo embryo production. Twenty-two crossbred ewes were used as embryo donors and assigned to two groups. Ewes from Traditional protocol were submitted to estrus synchronization with CIDR for 14 days and superovulation treatment was induced 60 h before the withdrawal of CIDR with 240 mg pFSH. Donors from Day 0 protocol were subjected to a short-term protocol of estrus synchronization (6 days) and superovulation treatment was the same to the other group, but it started 84 h after CIDR withdrawal. Embryo recoveries were performed using the transcervical method. All embryo donors (100%) presented estrus regardless of the hormone protocol used. The treatments did not affect the ovarian response, as well as quality and viability of embryos (P > 0.05). Treatments had a small dispersion of estrus, 81.81% (9/11) animals from the Traditional protocol group presented estrus 20 h after CIDR withdrawal and 90.9% (10/11) of the Day 0 protocol group presented estrus 24 h. Regarding embryo production, there was no significant difference between hormonal treatments for the different parameters evaluated (P > 0.05). It can be concluded that the Day 0 protocol was not different from the Traditional protocol in crossbred ewes.