Productive performance of Brazilian Somali ewes in the tropical Northeast region of Brazil

Abstract

Mean age at puberty was 333.4 days when ewes weighed 18.3 kg. First lambing occurred at 531.8 days and 22.2 kg body weight. Ovulation rate at puberty was 1.05 at first 1.13 at second ovulations. In laparotomized lambs, 87.5 percent ovulated before first puberal estrus and right ovary appeared to be more active. In rainy and dry seasons respectively, the estrus cycle length was 18.91 and 18.26 days and estrus period was 29.20 and 30.77 hours, being longer in older ewes (28.01 vs 31.23 hours). There was no significant difference in fertility rate at parturition and abortions, due to age of ewes. The mean gestation period was 148.7 days and sex ratio of lambs was 47.80. Overall prolificacy was 1.26 and 1.10 and 1.32 for primipara and pluripara ewes respectively. There was a marked difference in mortality of lambs born to primipara (19.05%) and pluripara (5.33%) ewes. Interval between parturition to first post-partum estrus was 70.13 days and interval between lambings was 281.3 days. Milk production averaged 211.7 g/ewe/day during first 80 days lactation. Mean birth weight was 2.02 kg and 10.5 kg at weaning. Mean body weight immediately before and after breeding season and at parturition were 25.2, 26.2 and 26.1 kg, respectively.