Efecto de la estimulación hormonal en vacas girholando sobre el número de folículos, recolección de oocitos y producción de embriones in vitro.
Chacón, L. | 2004-07
This study was designed to determine the effect of stimulation with or without FSH on the production of follicles, oocytes and in vitro embryos in Qyr cows, using an ovum pick up system. Aspirations were carried out once weekly for five weeks. The first one was done without gonadotrophin for both groups. The ovarían stimulation with constant dosages of FSH, determined an increase on the follicle production with a superior size to 2 mm compared with not stimulated cows. Furthermore, the numberof médium follicles size (5-10mm) at 2, 3, 4 and 5 weeks (p<0.05) was higher, as well as larger follicles (> 10 mm) at 3, 4 and 5 weeks (p<0.05). The number of small follicles remained constant during all aspiration weeks. The average number of oocytes classified as excellent, good and regular collected per cow per treatment was: 5.1 ± 0.9 with FSH and 2.2 ± 0.4 without FSH (p<0.05). The aspiration rate was 65% in all animáis. Oocytes recovered during the second week were matured, fertilized and the presumptive zygotes were subjected to in vitro culture during seven days. Transferable embryo production was higher in stimulated cows (17.7%) than in cows not treated with FSH (7.7%). In conclusión, the ovarían stimulation with FSH allowed an ¡ncrease of follicles with a size superior to 2 mm of diameter; the aspiration rate of oocytes was 65% for both treatments and the obtained births carne only from cows that were stimulated.