Proceedings
The breeding activity of 2166 native goats running permanently with intact bucks in 4 semi-intensive commercial flocks in an arid zone of Venezuela was studied from November 1976 to October 1980. The annual distribution of estrus and conception frequencies showed at least two peak periods of seasonal activity across the year; the principal one occurring in September (21.7 percent) or August-September (30.5 percent) and the minor season in May (19.6 percent) or May-June (27.4 percent) with large inter-year and inter-flock variations. The breeding season was highly correlated (r equal 0.66) with the onset of the rainy season and consequent availability of feed. Temperature and light appeared to have no influence. The lengths of the oestrus period and the estrous cycle were observed in 92 female kids (12-18 mo. 24.6 kg) and 410 multiparous does (2-6 years, 34.8 kg) during the 2 main periods of sexual activity. The cycle length averaged 20.6 + 3.2 days but was significantly shorter in young kids than in adults (P less than 0.05). Short cycles of 3-10 days occurred in 17.3 percent of all observations and were more common in maidens (P less than 0.01). Conversely, long cycles of 29-56 days were significantly more common in adults; (P less than 0.01). Short cycles were more frequent at the beginning of the principal and minor breeding season (P less than 0.01). The standing estrous ranged from 10 to 51 h (mean, 32.4 hs) and was shorter in young kids than in adults (29.6 vs 34.2; P less than 0.05). Young goats had 18 percent of cycles shorter than 25 h and adults had 39 percent longer than 35 h (P less than 0.01)
| Main Authors: | , , , |
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| Format: | biblioteca |
| Published: |
Scottsdale, AZ (EUA)
1982
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| Subjects: | CAPRINOS, REPRODUCCION, ESTACIONALIDAD, FACTORES AMBIENTALES, CICLO ESTRAL, VENEZUELA, |
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