Effect of Type and Time of Hormonal Treatment in Induction of Estrous and Ovulation in Shami Cows

M. AL-Dakkak, S. Salhab


Twenty six Shami cows available in Dier-Al-Hajar Station for improving Shami cattle were used to determine efficiency of two estrous synchronization methods during growing or regression of dominant follicle at the first follicular wave in follicular dynamics and estrous time in Shami cows. GnRH was injected intramuscularly (i. m.) on day 5 (group1: n=8; group3: n=8) or on day 9 (group2: n=8; group4: n=5) of estrous cycle, while controlled intra-vaginal drug release device (CIDR) was inserted at time of GnRH injection for 7 days in groups1 and 2. Prostaglandin was injected i.m. in all cows after 7 days of GnRH treatments. Transrectal ovarian ultrasonography was performed daily to monitor ovarian follicular dynamics and corpus luteum formation. Results indicated that time and type of treatment had a significant effect (p < 0.01) on follicular dynamics of small (5 mm) and large follicles (≥ 9 mm). All treated Shami cows were complied to estrous synchronization protocols showed estrous after 49.54±1.15 h of PGF2α injection, and ovulation after 72.46±1.05 h of PGF2α injection. However, type of treatment didn’t affect significantly the time of estrous and diameter of the dominant follicle at estrous, time of ovulation was also delayed (P< 0.05) after PGF2α injection in group 4 (76.85±2.21 h) in comparison to group 1 (68.96±1.77). It was concluded that estrous synchronization during growing or regression of dominant follicle in Shami cows by using PG-GnRH method reduce costs of treatments without any negative parameters on studied parameters versus CIDR method.


Gonadotropin Releasing Hormone (GnRH), Prostaglandin (PG), Ovarian Follicular Wave, Shami Cattle

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