Din\ue1mica folicular durante el Ciclo Estral en yeguas bajo condiciones tropicales

Se caracterizo la din\ue1mica folicular durante seis ciclos estrales (CE; periodo comprendido entre dos ovulaci\uf3n consecutivas) de yeguas purasangre de carrera en el tr\uf3pico, durante la estaci\uf3n de monta fisiol\uf3gica (julio- septiembre). El d\ueda de la ovulaci\uf3n, fue el d\ueda cero (0) del CE. Los fol\uedculos fueron clasi?cados en: C1 (\ua3 15 mm), C2 (16 - 25 mm), C3 (26-34 mm) y C4 (335 mm). La duraci\uf3n promedio del CE fue de 22,8 1 0,8 d\uedas. Se evidencio tres tipos de ondas foliculares, ondas mayores (OM; primaria y secundaria) y ondas menores (Om). El fol\uedculo dominante (FD) de la OM primaria emergi\uf3 el d\ueda 9,7 1 2,1 del ciclo, con un di\ue1metro de 7,2 1 0,5 mm. La divergencia del FD fue el d\ueda 5,8 11,3 de la onda, cuando el FD midi\uf3 20,0 1 2,1 mm, alcanzando un di\ue1metro m\ue1ximo de 41,3 11,9 mm. Los intervalos emergencia-divergencia, divergencia-ovulaci\uf3n fueron de 5,8 11,3 y 7,3 1 0,7 d\uedas respectivamente. El FD de la OM secundaria emergi\uf3 el d\ueda 2 del CE con un di\ue1metro de 11 mm. La divergencia ocurri\uf3 el d\ueda 6 de la onda, cuando el FD midi\uf3 25 mm, y el di\ue1metro m\ue1ximo alcanzado fue de 32 mm, el d\ueda 10 de la onda. El intervalo emergencia-divergencia fue de 6 d\uedas. En dos CE se evidencio ovulaciones dobles, emergiendo ambos FD el d\ueda 11,5 del CE, con un di\ue1metro de 8 mm en promedio, y con di\ue1metros m\ue1ximos de 42 mm y 39 mm respectivamente. El promedio de Om por CE fue de 6,8 1 2,6. El fol\uedculo de mayor tama\uf1o emergi\uf3 con un di\ue1metro de 8,5 1 0,3 mm, alcanzando un di\ue1metro m\ue1ximo de 20,2 1 0,4 mm el d\ueda 6,0 1 0,4 de la onda. Con base en estos datos; las yeguas que conformaron este estudio presentaron un comportamiento de la dinamia folicular similar al observado en yeguas mantenidas en otras latitudes. ABSTRACT Follicular Dynamics during Estrous Cycle in mares under tropical conditions The purpose of the present study was to evaluate the follicular dynamics of estrous cycles (EC) in thoroughbred open mares, under tropical conditions, during the ovulatory season (July-September). Follicles were monitoring and measured daily during estrous cycle (EC). The average length of the EC was 22,8 1 0,8 days. Three types of follicular waves primary (PMW), were observed secondary major waves (SMW) and minor waves. oooooof theence ofthe dominant follicle (DF) of PMW occurred on day 9,7 1 2,1 of the cycle, when the DF was 7,2 1 0,5 mm in diameter. Divergence into a DF and subordinate follicles (SF) occurred on day 5,8 11,3 of the wave, when the DF was 20,0 1 2,1 mm. The maximum diameter reached by the DF was 41,3 11,9 mm. The intervals from emergence to divergence and divergence to ovulation: 5,8 11,3 and 7,3 1 0,7 days, respectively. Emergence of SMW occurredoooooof theay 2 ofthe EC, when the DF was 11 mm of diameter. Divergence occurred on day 6 of the wave, when the DF was 25 mm of diameter, the maximum diameter reached by a DF of a SIVIW was 32 mm on day 10 of the wave. The interval from emergence to divergence was 6 days. Double ovulations were observed in two EC, emergence of the DF was on day 11,5 of the EC, when follicles were 8 mm in diameter. Maximum diameters reached by dominant follicles were 42 mm and 39 mm, respectively. The growing rate of DF was 3,2 mm/day. There were, in average, 6,8 1 2,6 minor waves per EC. The average diameter at emergence of the largest follicles of a minor waves was 8,5 1 0,3 mm., while the maximum diameter reached was 20,0 1 0,4 mm on day 6,0 1 0,4 of the wave. These results suggest that follicular dynamics in mares under tropical conditions, has similar characteristics to follicular dynamics of mares raised in others latituds