Seasonal Changes of Some Reproductive Traits in Farafra Ewes under Egyptian Environmental Condition

Abstract

AbstractThirty Egyptian Farafra ewes were used to study the effect of seasonal variations on reproductive cycleand ovarian activity. Estrus was detected twice daily throughout the year. Percentages of ewes showingestrus monthly, number of estrous cycle/ewe/season, estrous cycle length and heat duration weremeasured throughout different seasons of the year. Changes in ovarian activity were examined usingLaparoscopy technique. Percentage of ovulated ewes, ovulation rate and number of large and smallfollicles were recorded over different seasons. The obtained results revealed that the highest activecycles were observed in autumn and summer (87.1 and 84%), while the lowest was observed in spring(64.3%). Percentages of ewes that exhibited normal estrous cycle length during winter, spring; summerand autumn were 73.3, 47.0, 64.0, and 44.5%, respectively. While, the percentage of the short estrouscycle length was high in autumn (37.0%). During spring, summer and winter, the percentages of thelong cycle length were 25.0, 20.0 and 20.0 %, respectively. The percentages of ewes showed normalheat duration during autumn was 63.0%, summer (56.0%) and spring (46.4%), while the percentage ofewes exhibited short heat duration were in spring (53.6%) and winter (50%). During autumn, ewesrecorded the longest (p 3 mm3) in diameterwere significantly higher (P<0.05) in winter. Plasma progesterone concentration was always the lowestat the onset of estrous, increased gradually to a maximum level in day 8 and remained until day 14 (lutealphase), then declined in day 16 in winter, spring and summer and at day 18 in autumn. In conclusion,subtropical Farafra ewes were almost cyclic throughout the year. Reproductive performance of Farafraewes still need more studies to reveal the strength and potential of this breed.