Diâmetro do folículo maior no momento da aplicação do estradiol e taxa de gestação em vacas submetidas à sincronização da ovulação para IATF

• Autor(a) principal: Brito Neto, Emílio Pereira de
• Data de Publicação: 2012
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/5107
• topic: Sincronização; Taxa de gestação; Diâmetro folicular; Synchronization; Gestation rates; Follicle diameter; CNPQ::CIENCIAS AGRARIAS::MEDICINA VETERINARIA::REPRODUCAO ANIMAL

This study was carried out to evaluate the effect of the follicle diameter at the moment of the application of the oestradiol (E2), on the gestation rate of cows that received hormonal protocol of prostaglandin F2&#945;, followed by E2 for subsequent FTAI. Forty seven crossbred cows Bos taurus x indicus presenting luteal cyclical activity ovarian and in lactation were used. The cows were given two mL (150&#956;g) of the synthetic analogous of PGF2&#945; (D+chloprostenol) through intramuscular (i.m.). The diameter of the highest follicle present (dominant) was measured by ultrasonographic exam. After 24 hours, the cows were given a treatment with two mL (2mg) of oestradiol (oestradiol Benzoate) via i.m., and they were again evaluated through ultrasound examination for measuring and certifying the follicular dominance. Then, they were divided into two treatments: Treatment 1 (cows from which the diameter of the dominant follicle was lower than 13mm) and Treatment 2 (cows from which the diameter of the dominant follicle was with dominant follicle of diameter &#8804; 13mm). After 48h from application of E2, the cows were artificially inseminated. The gestation diagnosis was accomplished at 30 and 100 days after AI by ultrasound via transrectum. Differences (P<0,05) of 76% (19/25) and 45.5% (10/22) were observed in the gestation rates for the animals of the Treatments 1 and 2, respectively. At the 10th day after AI, the serum concentrations of progesterone were 1.34 ± 0.49 and 2.16 ± 1.17 for the Treatments 1 and 2 respectively, as showing differences between them (P<0.01). However, there was a low correlation (r = 0.45) between the serum progesterone concentration at ten days after AI and the gestation presence. It is concluded the follicular diameter at the moment of the E2 application to affect the fertility of the dairy cows, with diameter lower than 13mm presented better results than those &#8805;13mm. In addition, the follicles with diameter &#8805;13mm formed the corpus luteum that produce higher amount of progesterone after the artificial insemination, what did not affected the gestation rate.