Factors associated with the evolution of digit health in Swiss dairy herds in a nationwide digit health program

The purpose of this study was to investigate the evolution of digit health (DH) on Swiss dairy farms participating in a nationwide DH program and to identify risk factors associated with poor DH. Specially trained claw trimmers recorded disorders of the digits electronically during routine trimmings between January 2020 and June 2023. The first part of the study was a nonrandomized controlled implementation study, comparing the evolution of DH in 75 herds that received professional on-farm risk assessments, as well as veterinary advice with 49 herds that did not. Overall DH improved over time in both groups, with no difference between the groups. Differences emerged when implementation rates of measures after on-farm risk assessment were considered: DH of farms implementing >50% of recommended measures improved significantly more compared with farms implementing ≤50%. Also, farms where cows predominantly suffered from infectious-related lesions improved significantly compared with farms where cows suffered predominantly from mechanical-metabolic-related lesions. The second part of the study consisted of a retrospective observational risk factor analysis with a larger population (498 farms). Here, greater improvement of DH on a farm over the study period was associated with a higher farm claw score (index for decreased DH) at the beginning of the study and longer duration of participation in the DH program. Moreover, less improvement of DH was associated with freestalls, with "valley area" farm sites, and with herds with Holstein Friesian cows as predominant breed. Our results suggest that, if implemented appropriately, measures issued by DH experts may improve DH. Furthermore, voluntary participation in a DH program in combination with routine electronic recording of DH data by claw trimmers seem to raise farmers' motivation to improve DH. Our results are useful for farmers and veterinarians as well as for establishing DH programs in other countries.