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Oestrus and Ovulatory Rresponse of Goats with Different Parity to Male Effect and Short-term Progestagen Treatment

The aim of this work was to determine the oestrus and ovulatory activity in goats of different parity after male effect having had different short-term progestagen treatments. In April, 15 nulliparous and 22 multiparous Serrana goats were treated with 20 or 30 mg of fluorogestone acetate sponges, starting 6 days before introduction of three active bucks in the flock. Before treatment, all goats were anoestrous. Oestrous behaviour and mounting acceptance were evaluated, every 8 h, until 80 h after buck introduction. Plasma LH levels were monitored until 24 h after onset of oestrus. Plasma progesterone was determined, twice weekly, from 2 months before until 10 days after buck introduction. An ovulation was considered when plasma P4 levels reached >0.5 ng/mL after buck introduction and confirmed by ultrasonographic detection of corpora lutea. Sub-oestrus (silent ovulation) goats were considered when ovulation occured without oestrous behaviour. Percent oestrus and ovulatory activities were similar between progestagen treatments. Oestrus behaviour was observed in 26.7% of nulliparous goats and 68.2% in multiparous goats. Sub-oestrus occured in 53.3% of nulliparous and only in 13.6% of multiparous goats. Ovulation occured in 90.9% nulliparous and 80% of multiparous goats. In conclusion, parity of females appears affect the oestrus behaviour response but not ovulation in goats exposed to male effect after progestagen treatments.

oestrus; ovulatory response; goats; parity; male effect; progestagen

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