رصد نشاط الجريبات المبيضية و علاقته بالبلوغ الجنسي في عجلات البقر الشامية

الملخص EN

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.The means of length wave (13.64±0.29 day), maximum size of dominant follicle (11.90±0.12 mm) and number of daily total follicles (≥2mm) (11.27±0.17 follicle) in the first month prepuberty were larger (P < 0.05) than the other prepubertal months.

It was concluded that ovarian follicles in Shami heifers develope in a wave-like patterm during prepubertal stages.

Puberty occurs according to the first ovulation and subsequent formation of a CL at the same location in the ovary at 400±21 days old and 250±11 kg weight.