Abstract—The aim of this study was to evaluate the follicular dynamics in ewes during a prolonged treatment with melengestrol acetate (MGA). Twenty non-pregnant ewes with 3.2 ± 0.3 BCS (scale 1-5), 40.18 ± 5.8 kg BW, and 3.25 ± 0.6 years old were supplemented daily with 0.22 mg of MGA for 17 days, and observed their follicular development. The follicles were identified as an echogenic structures. The two largest follicles observed were identified, monitored and measured daily until they reach its maximum size (> 5 mm) and their consecuent follicular atresia at the end of each wave. The most of the ewes (85%) treated with MGA showed three follicular waves and the remaining 15% only show two waves. None of the ewes was observed ovulating during the period of treatment. The diameter of dominant ovulatory follicles observed had a variation from 5.5 ± 0.8 to 6.6 ± 0.5 mm. The duration of follicular waves was similar to those reported else. It’s concluded that using this doses of MGA is suppressed the ovulation without effect on the follicular dynamics in ewes, allowing normal development of dominant follicles and the manifestation of ovulatory follicular waves.

Index Terms—Ewes, follicular dynamic, melengestrol acetate.

Guillermo Salas-Razo, Jesús Antonio Rojo-Martínez, Ernestina Gutiérrez-Vázquez, Aureliano Juárez-Caratachea, Rogelio Garcidueñas- Piña and José Luis Espinoza-Villavicencio are with the Universidad Michoacana de San Nicolás de Hidalgo, Mich. México (e-mail: gsalas55@hotmail.com, jesus.red@hotmail.com, ernestinagv@hotmail.com, ajuarez1952@hotmail.com, rgarcidu@yahoo.com.mx, jlvilla@uabcs.mx) .

 

Cite:Guillermo Salas-Razo, Jesús Antonio Rojo-Martínez, Ernestina Gutiérrez-Vázquez, Aureliano Juárez-Caratachea, Rogelio Garcidueñas-Piña, and José Luis Espinoza-Villavicencio, "Follicular Dynamic in Ewes during Melengestrol Acetate (MGA) Treatment," International Journal of Bioscience, Biochemistry and Bioinformatics vol. 3, no. 4, pp. 360-362, 2013.