Influência do número de folículos antrais na eficiência reprodutiva de fêmeas da raça Senepol

Abstract

In vitro embryo production (IVP) and artificial insemination (AI) are two important techniques used to improve reproductive performance, production and genetic gain, so attention is needed to maximize results. Antral follicle count (ACF) is the number of follicles visualized by ultrasound in the ovaries. The literature shows that the use of the ultrasound exam can be classified as Beef according to the number of antral follicles, in three different groups: low, intermediate and high antral follicle count. Studies show for different reasons a relationship between ACF and in vitro embryo production and conception rate. The objective is to evaluate, in Senepol cattle, a relationship between antral follicle count and in vitro embryo production, precocity and exhibition rates. In experiment 1 was evaluated the relationship between ACF and viable, cleaved and total embryo oocytes, and in experiment 2 was evaluated the relationship between ACF and precocity (determined by the presence of corpus luteum), and between ACF and heifer conversion rate. . By ultrasound examination in the ovaries, the animals were evaluated and classified as low ACF (20 ≤ antral follicles), intermediate ACF (≥ 25 ≤ 45 antral follicles) and high ACF (≥50 antral follicles). The relationship between CFA and viable oocytes (R2 = 0.96), cleaved (R2 = 0.69) was detected. the total number of embryos (R2 = 0.34), but there was no effect of CFA on the conversion rates of viable oocytes into embryos. Heifers with intermediate ACF and high ACF tendency to be precocious. There was no relationship between ACF and conception rate in the first AI of heifers. It was concluded that in the evaluated group, Senepol with high ACF can produce a greater quantity of viable oocytes, cleaved and total embryos, and as heifers with intermediate ACF and high frequency it is earlier, but there is no relationship with heifer indexes up to 24 months.