White-line disease and haemorrhages in hooves of Finnish dairy cattle.

The Finnish Healthy Hooves Project was set up to determine the frequency of, and risk factors for, various hoof lesions in Finnish dairy herds. Data were collected in 2003 and 2004. A large data set of >74,000 cow-level observations recorded by hoof-trimmers were merged with production data from the Finnish Agricultural Data Processing Centre Ltd. Ultimately, data from a single lactation from each of 16,727 cows in 703 herds were used for analyses of white-line disease (WLD) and haemorrhages-lesions. Three-level hierarchical logistic models with hoof-trimmer and farms (within hoof-trimmer) as random-effects were fit to datasets of tie-stall (TS) and loose-housing (LH) herds separately. Cows examined once had a WLD risk of 4.8% in TS herds and 17% in LH herds. As the number of examinations increased, the odds of a WLD diagnosis increased substantially; (2 and 3+ examinations had odds ratios (ORs) of 2.57 and 3.40 in TS herds and 2.32 and 4.67 in LH herds, respectively, compared to 1 examination). Parity had an interaction with breed in all models in TS and in the LH haemorrhages model, but not in WLD LH models. In TS herds, older Holstein cows had a very high risk of WLD compared to young Ayrshire cows (OR=7.92). Also in LH herds both breed and parity had association with WLD (Holstein cows were 1.57 times more likely than Ayrshire cows and cows in parity >or=4 were more likely (OR=2.89) than parity 1 to get WLD). In TS herds, other hoof lesions - such as haemorrhages (OR=1.65), heel-horn erosions (OR=1.77), and corkscrew claw (OR=1.82) - increased the risk of WLD. In LH herds, corkscrew claw (OR=1.59) and heel-horn erosion (OR=0.72) had a significant association with WLD. In TS herds, use of mats (compared to hard flooring) significantly reduced the risk of WLD and haemorrhages (OR=0.57 and OR=0.80, respectively). No significant associations of the 305-day milk production on the risk of either disease were observed in either TS or LH herds (305-day milk yield from each cows' previous lactation were used for calculations, with herd average yield and the individual cow's deviation from the herd average being used as predictors).