Monitoring the ovarian follicular activity with relative to puberty in growing Shami heifers

Twelve growing Shami heifers available in Dier-Al-Hajar Station for improving Shami Cattle weighing 115±3 kg and 178±4 days old were used to monitor the daily growth of ovarian follicles (daily numbers, size, length and number of waves, rate of growth and regression) using Transrectal Ultrasound Echo System (7.5 MHz probe) in 6-14 months-old heifers. Results indicated that ovarian follicles developed in a wave pattern in all Shami heifers when they were 6 months old and no significant differences in the number and size of ovarian follicles were found between right and left ovaries. A cohort of 4 to 7 small follicles with a diameter 2-5 mm developed together and one of them was selected for continual growth, became dominant and later regressed during the pre-pubertal stage.