Genetic relationship between body condition score, fertility, type and production traits in Brown Swiss dairy cows

This study aimed to investigate the relationship between body condition score (BCS), calving interval (CI), angularity (ANG), strength (FV) and milk yield (MY) on Brown Swiss cattle using data collected in the alpine provinces of Bolzano- Bozen and Trentino. The data set consisted of 28,538 test day records of BCS and MY from 3,282 Brown Swiss cows in lactation reared in 109 herds; production traits were merged with 13,796 repeated individual calving interval records and 38,711 type traits records. A multi-traits REML animal model was used to estimate (co)variance components, with repeated observations. Heritability estimates for BCS, FV and ANG was 18%, 18% and 27%, respectively, while estimates for CI was very low (2%). Genetic correlations between CI and BCS was -0.44; between BCS and ANG was - 0.64; between BCS and MY was -0.35; between ANG and CI was 0.12. In conclusion, the selection for MY and ANG negatively affect fertility and average condition score of Brown cows. BCS recorded during lactation could be proposed as a useful trait for indirect selection aimed to improve fertility of cows.