ABSTRACT The objective of this work is to estimate genetic parameters and breeding values to improve embryo and oocyte production, using repeatability and random regression models (RRM) for Gir dairy cattle. We used 11,398 records of ovum pick-up from 1,747 dairy Gir donors and evaluated sixteen different models: the traditional repeatability model and fifteen RRM, each of which considered a different combination of Legendre polynomial regressors to describe the additive genetic and permanent environment effects. The 4G1P model (four regressors […]

This study evaluated the influence of follicular fluid (FF) added to the maturation medium on the quality of bovine embryos produced in vitro. In the first experiment, oocytes were matured in media containing five different FF concentrations with different maturation times and classified according to meiotic progression and migration of cortical granules. In the second experiment, oocytes matured in the same media were fertilized at three different maturation times; thereafter, cleavage and blastocyst rates were evaluated. In the third experiment, […]

A simulation model implemented in the programming software Delphi XE® was applied to evaluate sex selection in bovine. The hypothesis under investigation was that a dynamic model with stochastic and deterministic elements could detect the sexed semen technique to minimize pregnancy cost and to determine the adequate number of recipients required for in vivo (ET) and in vitro embryo production (IVP) in the proposed scenarios. Sex selection was compared through semen sexed using flow cytometry (C1) and density gradient centrifugation […]

The methodology of in vitro embryo production in ovine requires the development of maturation, fertilization and culture media, in order to increase cleavage and development rates. This, in turn, would improve the implement of biotechnological programs for commercial purposes, as well as the use of this technique for cloning and transgenesis in this species. From the point of view of research, the oocytes can be obtained by puncture or slicing of ovaries collected from abattoirs, or by laparospic follicular aspiration […]

The development of in vitro embryo production (IVP) methodology to maximize genetic gain and animal production at lower cost is a challenge of the research and it has been studied for many years. The possibility to produce, in commercial scale, embryos from ovum pick up methodology may increase the benefits of the use of artificial insemination (AI) for its decisive role to maximize the genetic progress between generations, according to the requirements of each genetic improvement program and livestock capacity. […]

This study aimed to evaluate the effect of different gonadotropin sources for in vitro maturation of bovine oocytes fertilized and developed in vitro on cleavage (CR) and blastocysts rates (BLR). The immature oocytes from slaughterhouse cows ovaries were matured in vitro under different conditions: TCM 199 medium with 10% eostrous cow serum (ECS), aditives, hepes, NaHCO3, sodium pyruvate, antibiotics (B-199 medium), 20 UI/mL PMSG and 10 UI/ml hCG (PMSG/hCG) or B-199 medium with 5 mg/mL FSH and 5 mg/mL LH […]

This study investigated the effect of semen extender on in vitro development of bovine oocytes after in vitro maturation and fertilization. The ejaculate from one bull was divided in three parts which were diluted with three different extenders: Egg yolk/Lactose (EYL), Egg yolk/Citrate (EYC) and Egg yolk/Tris (EYT). Samples of semen diluted with these extenders were frozen in liquid nitrogen and, after thawing, were filtered by discontinuous Percoll gradient. The sperm concentration was adjusted to 10 x 106 cells/mL and […]