RESUMO
In vitro embryo production and embryo vitrification of genetically superior cows that culled inevitably due to health problems can accelerate genetic progress. This study was carried out to investigate whether maternal age and health status effects of high genetic merit cows affect cryosurvival and developmental competence of IVP embryos. In this sense, the effects of ageing and four common culling causes of dairy cows [repeat breeding (RPB), udder problems (UPM), chronic endometritis (CRE), and lameness (LAM)] on in vitro embryo development, and in vivo developmental competence after embryo vitrification were evaluated. The mean number of oocytes obtained per cow did not vary significantly between donors indifferent groups. Cleavage rates in RPB (86.0+/-4.2%), SEN (81.3+/-2.5%) and CRE (77.6+/-6.3%) cows which were comparable to control (95.9+/-1.5%) but were significantly higher than the related rate of UPM donors (50.6+/-2.6%). Importantly, there was no significant difference between the blastocyst rates of different groups. Mean overall survival rate was not different between the groups and was not affected by the blastocyst production rate. There was no significant difference between pregnancy rates of different groups. The results of the present study indicated that in cattle, neither ageing, nor these four diseases affect ovarian potential in terms of the yield and quality of in vitro embryo development.
