Evolution studies from embryo transfer and in vitro fertilization in Nelore cattle at Brazil

Data from Brazilian Association of Zebu Breeders were used to show the evolution of conventional embryo transfer (ET) and in vitro fertilization techniques between 1997 and 2007 for the Nelore cattle in Brazil. Data from 109.775 conventional embryo transfer and 73.121 ovum pickup (OPU) were used. The embryo transfer supremacy was observed until 2004 when a considerable increase of OPU number over ET occurred. More ET and OPU were carried out in Southeast and Mid-West than in others Brazilian regions. The average number of viable embryo along the analysis period is close to that reported by literature (between 5 and 7 embryos per flushing or OPU session).