Effect of lameness on the calving-to-conception interval in dairy cows

Objective-To examine the relationship between lameness and the duration of the interval from calving to subsequent conception in lactating dairy cows. Design-Cohort study. Animals-837 dairy cows. Procedure-Cows affected with lameness were classified into 1 of 4 groups on the basis of types of disease or lesions observed, including foot rot, pap illomatous digital dermatitis, claw lesions, or multiple lesions. Cows not affected with lameness were classified as healthy. Time from calving to con ception was compared between lame cows and healthy cows, Results-254 (30%) cows were affected with lameness during lactation. Most l ame cows (59%) had claw lesions. Lame cows with claw lesions were 0.52 time s as likely to conceive as healthy cows. Median time to conception was 40 d ays longer in lame cows with claw lesions, compared with healthy cows. Numb er of breedings per conception for lame cows with claw lesions was signific antly higher than that for healthy cows. Conclusion and Clinical Relevance-Claw lesions were the most important caus e of lameness, impairing reproductive performance in dairy cows, as indicat ed by a higher incidence of affected cows and a greater time from calving t o conception and a higher number of breedings required per conception, comp ared with healthy cows.