Infuence of heat stress on in vitro oocyte and embryo production in high-yielding Holstein cows

Abstract The objective of this study was to evaluate the influence thermal shock on oocytes used in production vitro embryos (IVP) high productivity Holstein cows day follicular aspiration (OPU; 0), 30, 60 and 90 days before OPU. From mean temperature 0 previous days, they were classifed into comfort group (TC; up 15°C) heat stress (HS; above groups.Anegative observed viable (total grade I). periods 30 prior OPU resulted lower (P=0.0028; P=0.0092, respectively). Under stress, (HS-OPU), showed no reduction amount (P=0.5497) there for stressed (P=0.8287). For total embryos, difference occurred only HS-30 (P=0.0317), where groups HS-OPU, HS-60, HS-90 presented, respectively, P=0. 1987, P=0.0596 P=0.4580. Regarding 1, HS-OPU (P=0.2291) (P=0.2868), but a (P=0.0143) HS-60 (P=0.0253). In summary, had negative impact when it or aspiration. addition, seems be period more susceptibility that causes greatest deleterious effects oocyte viability IVP.