Hoof lesions and lameness in Swedish dairy cattle: prevalence, risk factors, effects of claw trimming and consequences for productivity

This thesis used hoof-health records obtained at claw trimming in 102 Swedish dairy herds during 2 years to study different aspects of hoof health. Most (72%) of the 4,899 trimmed cows had at least one hoof-lesion whereas 5.1% were lame. Hoof lesions and lameness were associated with both individual- and herd-level risk factors. Individual (cow) level risk factors were of greater importance for explaining variation associated with claw-capsule defects than for skin lesions. Except for claw-horn haemorrhages, hoof lesions were more common in multiparous than in primiparous cows. Moreover, the risk of lameness and hoof lesions (except dermatitis) further increased with parity. Swedish Holsteins were at an increased risk of haemorrhages and sole ulcers compared to other breeds. Cows at 61-150 days in milk were at increased risk of haemorrhages and sole ulcers. Heifers that had calved at a relatively low age were at a decreased risk of hoof lesions. Cows with dirty hooves were at an increased risk of lesions and lameness. The risk of dermatitis or heel horn erosion was three times higher in cows housed in loose-housing systems than in tie-stalls. There was a negative effect of lameness on longevity (increased risk of culling within the same lactation) and of hoof lesions on reproductive performance. Significant negative associations were found between sole ulcer and first-service conception rate, calving interval, and treatment for anoestrus. Cows with sole ulcers had a higher milk yield than cows without, indicating that high-producing cows are more prone to develop the disease. Claw trimming in autumn reduced both the risk of lameness and hoof lesions in the following spring (~4.5 months later) and the need for acute hoof treatments between trimmings. The results of this thesis demonstrate the importance of hoof health for dairy cow productivity, and of claw trimming in maintaining and restoring hoof health