Reproductive pattern of local sheep in Egypt with special reference to the effects of breed, season and management

The effect of season on ovulation has been monitored in two local breeds of Egyptian ewes - the Barki (desert type), and the Rahmani (fat tailed Nile valley breed), by sequentially measuring cyclic changes in plasma progesterone concentration throughout a period of one year in the absence of any possible ram effect. The modal length of the ovulatory cycle was 17-18 days for both breeds, with the progesterone concentration peaking around day 11. No effect of season on progesterone concentration was apparent for the Barki breed but in the Rahmani, progesterone values were lower (P < 0.05) during the summer than during the autumn months. While the Barki have a restricted breeding season from June to November, the Rahmani have only a short period of anovulation within April. Thirty-three per cent of the Rahmani breed were identified as having cycled throughout the year. (author). 9 refs, 4 figs