Effect of ascorbic acid on the conception rate of Yankasa ewes after estrus synchronization

Abstract

The objective of this study was to evaluate the effects of ascorbic acid (AA) on the conception rates in ewes following progestin treatments. Yankasa ewes (n = 64) were equally allocated into two groups. One group was treated with controlled internal drug-released (CIDR) intravaginal devices, the other with 45 mg fluorogestone acetate (FGA) intravaginal sponges. After withdrawal of pro­gestin, ewes that exhibited estrus were further allocated into four subgroups for the administration of AA during estrus expression: CIDR control (CDNN, n = 12), CIDR plus AA (CDAA, n = 11), FGA control (FGNN, n = 13), and FGA plus AA (FGAA, n = 12). Estrus detection and natural mating were carried out with sexually active rams. The proportion of ewes in estrus did not differ between subgroups. The interval from withdrawal of devices to onset of estrus was significantly (p < 0.05) shorter in the FGA than in the CIDR group (30.35 ± 2.72 and 48.56 ± 7.52 hours, respectively). The duration of induced estrus did not differ (p < 0.05) between treatments (FGA 37.22 ± 4.22 and CIDR 39.75 ± 2.51 hours). Conception rates were comparable between subgroups. We therefore concluded that the administration of AA at sponge withdrawal did not improve the conception rate in Yankasa ewes treated with progestins.