Prevalence of thin soles in the hind limbs of dairy cows housed on fully-floored vs. partially-floored mastic asphalt areas in Austria.

Excessive sole horn wear in cattle due to abrasive floors, such as new concrete and mastic asphalt, and excessive sole trimming, are the leading causes of thin soles. This study compared prevalence of thin soles in Austrian dairy cows in six herds housed on fully-floored mastic asphalt (FMA) or partially-floored mastic asphalt (PMA). All cows had last received hoof trimming at least 5 months before the study commenced. Sole horn thickness of the hind claws was measured ultrasonographically in 97 cows at two points on each claw: (1) point 1 exactly at the tip of the pedal bone surface; and (2) point 2 approximately 3cm caudally. Locomotion was scored in all cows and claw lesions were categorised using a computerized claw trimming database program and evaluated at cow- and claw-level. An ANCOVA-model was applied to calculate the effects of different factors (breed, age, farm, days in milk) and covariates on sole horn thickness. The cut-off measurement for thin soles was defined as ≤4.5mm, in accordance with a recent study. Regarding claw health, FMA areas were inferior to PMA areas in barn installations. In cows on FMA, the prevalence of thin soles was significantly higher (P=0.01) and mean sole horn thickness at point 1 was significantly lower (P=0.01) than cows on PMA (59.7% vs. 12.5%; 5.35 mm vs. 6.63 mm, respectively). There were also significantly more lame cows on FMA than on PMA (P=0.01). The FMA group had higher prevalences of white-line disease (59.6% vs. 25%; P=0.01) and toe ulcers (12.3% vs. 0%; P=0.02) than the PMA group.