RECUPERAÇÃO DE OÓCITOS EM DOADORAS GIR E GIROLANDO

Abstract

The Girolando breed, at first, was generated with the intention of having a Brazilian descent that was qualified for milk production. The dairy Gir, on the other hand, is the Zebu cattle with the highest rate of production efficiency under tropical conditions. In cattle, the process of in vitro embryo production (PIV), in partnership with ultrasound-guided follicular aspiration (OPU), appears as a tool to enhance reproductive competence. Thus, the objective of this study was to compare the performance of Gir and Girolando females in terms of the number and quality of oocytes recovered using the OPU technique and after in vitro culturing of oocytes. To this end, data were collected on follicular aspirations guided by ultrasound and in vitro oocyte culture (CIV) from donors of the Gir and Girolando breeds, during the years 2013, 2014 and 2015. A total of 113 donors, 41 of which are Gir and 72 are Girolando. The characteristics analyzed were: number of total, viable and non-viable oocytes, quantity of oocytes grade I, II, III and% of viable oocytes after in vitro culture, in addition to the evaluation of the significance of the effects (races and years) by Analysis of Variance using the PROC GLM procedure of the Statistical Analysis System. The comparison of the breeds' performance indicated Girolando as the holder of the best results. Showing values of 32.20 ± 14.51 for total oocytes, 26.91 ± 12.37 viable oocytes, 3.53 ± 3.90 grade 1 and 28 oocytes, 15 ± 13.72 for the% of viable oocytes after CIV. This is thanks to a trait that is considered its great asset: heterosis. Meanwhile, the Gir breed showed 25.28 ± 13.22 total oocytes, 21.31 ± 11.94 viable oocytes, 2.24 ± 3.36 grade I oocytes and 21.99 ± 11.99 for the% of viable oocytes after CIV. The analysis of quadratic regression as a function of months was significant (p <0.05) for non-viable oocytes, grade I and grade III. In this context, in vivo and laboratory knowledge supports the idea that oocytes from bovine females are vulnerable to thermal stress. The phenotypic correlation attested that the selection of Gir and Girolando females for genetic improvement plans must be made according to the amount of total oocytes produced per female, because this ability is highly phenotypically correlated with grade II oocytes (r = 0.74 ), viable oocytes (r = 0.96) and% viable after in vitro culture (r = 0.92). It was concluded, then, that Girolando females had better performance for quantity and quality of oocytes. They were also higher in the proportion of viable oocytes after in vitro culture.