Comparative study of oestrous activity in Finn ewes and two Egyptian fat-tailed sheep under subtropical conditions

Abstract

SUMMARYOestroua activity of three flocks of Ossimi (O) and Rahmani (R) subtropical fattailed and imported Finn (F) ewes was followed over a calendar year under the prevailing subtropical conditions in Egypt.Rahmani had quite consistent oestrous activity throughout the year, with a slight drop in March and June, and may be regarded as a non-seasonal breed. Oestrous activity of the O ewes was lower than the R at different times of the year. They showed high individual variation. Most of the O ewes had an anoestroua period during July–September but had regular oestrous activity during their breeding season.Overall number of oestruses per ewe per year was 15·9, 13·0 and 10·3 for R, O and F, respectively. Normal cycle length tended to be longer, though not significantly so, in both R and O subtropical breeds than the F (17·8 and 17·6v. 17·1 days). Heat duration was significantly longer in F (47·0 h) than in both local breeds (37·7 and 37·5 h for R and O, respectively).