Morphokinetic prediction of embryo viability in cattle

Conventionally, bovine in vitro-produced (IVP) embryos for transfer are morphologically evaluated at day 7–8 of embryo culture, as recommended by the International Embryo Technology Society (IETS). However, this method is subjective, relying on the percentage of degenerated cells and developmental stage, leading to variability depending on the operator. In contrast, we have implemented a novel selection system for bovine IVP blastocysts using time-lapse monitoring in specially developed microwell culture dishes (LinKID micro25). This approach allows for continuous tracking of individual embryo development. Additionally, we have advanced live-cell imaging technology to observe nuclear and chromosomal dynamics during early embryogenesis, identifying prognostic factors indicative of viability post-transfer. Integrating these factors has significantly improved conception rates compared to conventional morphological evaluation. This review discusses morphokinetics relevant to viability and our innovative selection system, which enable accurate prediction of embryo viability after transfer in cattle.