Seasonal Variations of Estrus and Ovulation in Native Maure Goats of Tunisia

Abstract

In an attempt to characterize seasonal variations of ovulation and estrous behavior, 22 adult non-pregnant Maure Tunisian goats were used. The experimental period lasted 14 months during which the goats were run on natural rangeland and supplemented with constant levels of concentrate (200 g/nanny goat/day). The goats were also exposed to natural photoperiod and kept in the presence of males. Aproned bucks were used twice daily to detect estrus, while ovarian activity was monitored monthly by laparoscopy. Throughout the breeding season, which occurred from September to March, 80% of the nanny goats exhibited estrus at least once and 53% of all estrous cycles were accompanied by ovulations. This season preceded a period of sexual inactivity (March-August). The incidence of abnormal short estrous cycles was higher at the end of the breeding season. During the month of September, 86% of the goats displayed estrus. A similar seasonal distribution was observed for cyclic ovarian activity, with the proportion of ovulating goats increasing gradually from September to reach 100% during December, and then declining to reach a minimum of 14% during March. The mean ovulation rate was 1.51 ± 0.29 with a maximum of 1.94 ± 0.74 at the start of the breeding season in September, and a minimum of 1.25 ± 0.50 at the end of this season in March. There was a zero evolution rate between April and August included and there was a significant difference (P < 0.05) between the start of the breeding season and the end. It was concluded that native goats in Tunisia, under semiarid grazing conditions, exhibited a seasonal pattern of reproduction.