This project aims to provide new insights and practical selection tools based on the SNP genotyping data accumulated in Switzerland over the last decade from more than 230 thousand cattle of all dairy breeds as well as some mother cow breeds. This will enable breeding measures to improve fertility and avoid reproductive and breeding losses. Scientific actors from animal genetics and genomics, together with the Competence Centre for Breeding Value Estimation, which operates on behalf of the Swiss Cattle Breeders' Association, are striving for an interdisciplinary research project to answer the following questions: To what extent do undesirable alleles and genetic variants that explain inherited traits and diseases occur and how do alleles that show a deficit of homozygosity manifest themselves. Furthermore, questions of immediate practical relevance will be addressed: How can the constantly increasing genetic information for the most diverse traits be combined to reduce the occurrence of undesirable genetic peculiarities in the long term, and what should an algorithm look like with which the increasing detailed knowledge can be taken into account in real time, immediately before planned matings. Current genetic-statistical approaches, veterinary expertise as well as extensive genome sequence data will be used in combination. The project promises to directly promote animal health, animal welfare, and profitability for Swiss cattle breeding.