Ovarian activity in Nubian goats during spring in Uruguay

Abstract

The objective of the present essay was to determine the ovarian activity in Nubian yearling does during springtime in Uruguay by measuring progesterone levels in blood and by observing corpora lutea and sexual behaviour. Twenty-five one-year-old female does were in continuous contact with a vasectomized buck from July to January. Progesterone levels from samples obtained every two weeks were determined by radioimmunoanalysis in solid phase. Corpora lutea were diagnosed by lapacoscopy performed once a month. Sexual behaviour was assesed with the used vasectomized buck once a day. All females showed ovarian activity until August 15th, then the percentage decreased gradually, arriving in the end of September to 100% of inactivity. The ovarian activity restarted in January, with the presence of short oestrus cycles with anovulation or formation of corpora lutea with low progesterone levels (<0.5 ng/ml) to finally acquire complete ovarian activity with normal oestrus cycle. The present study concludes that ovarian activity was absent during Spring in Nubian yearling does,¡.