Reproductive parameters of Santa Inês ewes submitted to short-term treatment with re-used progesterone devices

Abstract

The aim of this study was to verify the efficacy of reusing intravaginal progesterone (P4) devices on the reproductive parameters in Santa Inês ewes. Females received intravaginal P4 devices for their first, second or third use for five days plus 300 IU eCG IM and 5mg dinoprost laterovulvar 24h before device removal. Blood was collected at different moments. Transrectal ultrasonography was performed from device removal to ovulation. Part of the ewes were submitted to artificial insemination by laparoscopy (IAL - n=55) with fresh semen, whereas the rest were bred by fertile rams (n=41). On the initial 18 h, ewes that received devices for the first time showed higher P4 concentrations (5.1±1.8 vs 3.5±1.4 vs 2.4±1.1 - P<0.05). However, after the first 48h no difference was observed among all treatments and P4 supraluteal concentrations were detected in all ewes upon device removal. Estrous response, interval from device removal to estrus, rate of ovulating animals, number of ovulations, time from device removal to ovulation and average conception rates after IAL or natural mating were similar among all 3 groups. Intravaginal progesterone devices can be used up to three times without altering reproductive parameters in Santa Inês ewes.