Locomotion problems are identified as major welfare problem for dairy cattle. The majority of locomotion problems is caused by claw disorders, either infectious or non-infectious. Although severe claw disorders usually are manifested by lameness, clinical lameness can be regarded as the top of the iceberg of claw and locomotion problems. The so-called subclinical claw disorders do presumably influence behaviour of the affected cows, but the changes are subtle and therefore difficult to observe. Improvement of claw health seems feasible in practice, but this requires that risk factors are managed. In this thesis only non-infectious claw disorders (e.g. sole haemorrhages, sole ulcers and white line disease), that are assumed to be caused by similar mechanisms, are considered. Housing and management have a large influence on claw health, and particularly flooring in the walking areas and provisions for lying are elements of housing that are related with claw health. The main objective of this thesis is to improve understanding of the aetiology of non-infectious claw lesions, and in particular the effects of mechanical load on claws.
For this study, two experiments were carried out at Waiboerhoeve research farm, Lelystad, the Netherlands. In the first experiment, effects of an alternative trimming technique were determined for mid-lactation cows kept in barns with either concrete or rubber topped slatted alley flooring. In the second experiment, effects of restrictions in access to the cubicles in the first 2 months of lactation were determined for heifers in their first lactation, again in combination with either concrete or rubber topped alley flooring. These experiments aimed to provide knowledge regarding the impact of claw shape, hard vs. soft flooring and restrictions of lying conditions on claw health and behaviour. To better understand the effects of lying and standing and of claw shape on claw health, a methodology was developed and applied to accurately measure load induced spatial deformation of lower hind limbs of cattle. The results enabled us to estimate the load induced compressive strain in the soft tissues between the sole horn layer and the distal phalanges, and to compare the strain distribution with the location of sole haemorrhages and sole ulcers.
From the experiments described in this thesis, it can be concluded that concave hoof trimming is not beneficial for dairy cows kept on either concrete or rubber topped flooring with regard to claw health or locomotion. Differences in claw shape due to trimming are undone quickly due to claw floor interactions. Rubber flooring reduces the prevalence and seriousness of haemorrhages and results in reduced growth and wear of the horn shoe. Moreover, cows spend more time standing in the alleys and are more active in a barn with rubber topped alley flooring. Presumably, this is because rubber flooring provides more comfort during standing for the cows. This could be influenced by formation of sole concavity, that helps to prevent overloading of soft tissue in the bulb area. The load deformation experiments showed that with flat soles soft tissues under the distal phalanx are already compressed at load levels that occur during standing. Moreover, there is a similarity between the location of high mechanical strain in the soft tissue layer and the location of sole horn lesions. Therefore, although reduced access to the cubicles did not measurably impair claw health in this study, it is likely that poor lying comfort resulting in prolonged standing bouts, particularly on hard and abrasive flooring, is detrimental for claw health.