Successful transcervical uterine flushing can be performed without or reduced dose of oestradiol benzoate in cervical relaxation protocol in Dorper ewes.

Abstract

This study assessed the efficiency of cervical relaxation protocol using none, half or full dose (1.0mg) of oestradiol benzoate in Dorper ewes subjected to non-surgical embryo recovery (NSER). Thirty-six pluriparous ewes received progestogen sponge (60mg) for 9days plus eCG administration (300IU i.m.) 24hr before sponge removal. Ewes were not mated and were randomly assigned to receive at 16hr before NSER 37.5µg d-cloprostenol i.m. and different doses of oestradiol benzoate: 0.0mg (0EB group; n=12); 0.5mg (0.5EB group; n=12) or 1.0mg of oestradiol (1.0EB group, n=12). All ewes received oxytocin (50IU) i.v. 20min before NSER, which was performed 8days after sponge removal. Corpora lutea were counted by transrectal ultrasonography 24hr before NSER. After procedure, the ewes were kept in natural breeding period to check their post-NSER fertility. NSER was performed in 91.7% (33/36) of the animals with overall fluid recovery efficiency over 97% (p>.05). The cervical transposing with Hegar dilator was longer (p<.05) in 0EB (4.2±0.3min) compared to 0.5EB (1.7±0.3min) and 1.0EB group (1.5±0.3min). The cervical transposing with mandrel/catheter was longer (p<.05) in 0EB (2.4±0.5min) than 1.0EB group (1.3±0.5min). Overall duration of uterine flushing was 25.4min with structure recovery rate of 43.5%, with no difference among groups (p>.05). The post-NSER fertility was higher (p<.05) in 0.0EB (90%) than 0.5EB group (36.4%). In conclusion, NSER can be successfully performed in Dorper ewes by using a cervical relaxation protocol without oestradiol benzoate.