Effect of season on the occurrence of oestrus and fertility in different breeds of sheep under semi-arid conditions
Sahni, K.L.; Tiwari, S.B.; Sahani, M.S.
Indian Veterinary Journal 53(7): 515-522
1976
ISSN/ISBN: 0019-6479 PMID: 1026659 Document Number: 102754
The observations were carried out on about 1000 sexually mature ewes comprising Rambouillet, Malpura, Chokla, Jaiselmeri and their crosses. The autumn season was superior to the spring in terms of oestrus activity as well as fertility. The incidence of oestrus was uniformly high in autumn (80-90%) irrespective of breed, but fertility in Rambouillet was only 33% as compared to 60-70% in other breeds. The incidence of oestrus was 50-60% in spring, and half-breds were observed to show only partial pattern of sexual activity, which was possibly attributed to the prevalence of high environmental temperature, decrease in availability of grazing material and increase in light hours. Only 40-50% of ewes lambed as a result of inseminations performed in spring.