Effect on oestrus and ovulation of exposing creole goats to the male at three times of the year

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Abstract
The characteristics of the estrous and ovarian cycles of local goats were studied over 2 yr, on 96 females in March, 60 in July and 100 in Nov. After 3 wk of separation between sexes, the females with inactive ovaries were identified and harnessed males were introduced. Detection of estrus was undertaken daily and the date and rate of ovulation were checked at laparoscopies. The proportion of females with non-cyclic ovaries before the mating period varied according to the season and whether the females were nulliparous or suckling. Among the females with inactive ovaries before the mating period, 97% ovulated 2.8 days after the introduction of males; 68% of these initial ovulations were accompanied by estrus and 76% resulted in short luteal phases (5.3 days) followed by a 2nd ovulation accompanied by estrus 89% of the time. The proportions of initial ovulations with estrus and of initial ovulations followed by a short luteal phase were in linear relationship with the proportion of females with non-cyclic ovaries before the mating period. For the females with cyclic ovaries before the mating period, the distribution of 1st estrus during the 8 days after the introduction of males was signifciantly different from the expected uniform distribution. A possible luteolytic action of teasing was suspected. The fertility of females in all groups was high (> 79%). Litter size was not different for non-cyclic and for cyclic females.