Reproductive seasonality in sheep
Gundogan M; Baki D; Yeni D
Abstract Unlike most domestic livestock species, sheep are widely known as animalswith marked seasonality of breeding activity. The annual cycle of the daily photoperiod has beenidentified as the determinant factor of this phenomenon, while environmental temperature,nutritional status and social interactions may modulate it. The aim of this paper is to review thecurrent state of knowledge of reproductive seasonality in sheep. Following general consideration ofthe importance of seasonal breeding as a reproductive strategy for the survival of the species, thepaper describes manifestations of seasonality in both the ram and the ewe. Both determinant andmodulating factors are discussed, and special emphasis is given to the neuroendocrine base ofphotoperiodic regulation of seasonal breeding. Other aspects such as the role of melatonin, theprogestogens and ram effects with or without anestrus period are also reviewed.
Keywords Anestrus; Melatonin; Photoperiod; Ram effect; Reproduction; Sheep;Ewe lambs;Corpus-luteum; Estrus; Ovulation; Synchronization; Ram;Performance; Melatonin; Fsh; Progesterone
Acta agriculturae Scandinavica. Section A, Animal science
0906-4702, Volume 53, Issue 4, 2003, Pages 175-179
