Factors affecting follicular dynamics in Rahmani ewes.

Abstract

Rahmani ewes (n=25) were used to investigate the effect of subcutaneous back fat (BF), body condition score (BCS), body weight (BW) and age on their follicular dynamics. Ewes were estrus synchronized using 2 doses of Cloprostenol 11 days apart. At the second dose, ultrasound was used to count follicles and measure their diameter for 5 successive days and counting corpora lutea 7 days after ovulation. Ultrasound also was used to determine BF parallel to the last thoracic vertebra. There is a significant increase in number of large follicles on the left ovary with the increase of back fat. Ewes with BF ≥1.5 mm have low medium follicles but high large follicles on their left ovaries and high large follicles and dominant follicles diameter on their right ovaries. The increase in back fat thickness was accompanied by a significant increase in ovulation rate (OR). Large follicles, total follicles and ovulation rate are low in ewes with back fat thickness 1mm and good body condition >2 and to delay those of low subcutaneous fat < 1mm and body condition <2 till they gain enough body reserves to result in an economically viable return from sheep flocks.