Combined treatment with estradiol benzoate, d-cloprostenol and oxytocin permits cervical dilation and non-surgical embryo recovery in ewes.

This study examined the feasibility of transcervical embryo recovery after the hormonal treatment to induce cervical dilation, following the 7-day estrous synchronization protocol in multiparous Santa Inês ewes. A total of 23 cyclic ewes received two doses of 37.5 μg of d-cloprostenol by latero-vulvar route seven days apart. After the second injection of d-cloprostenol, the ewes were checked for estrus (every 12 h) and then mated by fertile rams throughout the estrous period. All ewes received 37.5 μg of d-cloprostenol (latero-vulvar) and 1 mg of estradiol benzoate by either intramuscular (EBim group; n = 12) or intravaginal (EBivg group; n = 11) route 16 h before embryo flushing. Twenty minutes before the flushing, 50 IU of oxytocin were administered intravenously. The estrous response (i.e., the percentage of ewes that showed signs of estrous behavior after the second d-cloprostenol injection) was 91.3% (21/23). The proportion of successfully penetrated ewes (81.8% compared with 80.0%), the mean duration of embryo flushing (24.7 ± 2.0 min compared 26.2 ± 1.9 min), the flushing fluid recovery rate (94.8 ± 1.3% compared with 91.0 ± 2.9%), and the average number of structures recovered per ewe (0.5 ± 0.4 compared with 0.8 ± 0.4) did not vary (P > 0.05) between the EBim and EBivg groups. Viable embryos were recovered from 41.2% (7/17) of successfully penetrated ewes. It can be concluded that non-surgical (i.e., transcervical) embryo collection can be performed in estrous-synchronized Santa Inês ewes pre-treated with d-cloprostenol, oxytocin and estradiol benzoate, with the latter hormone administered by either the intramuscular or intravaginal route. This article is protected by copyright. All rights reserved.