Relative importance of factors influencing the prevalence of lameness in Austrian cubicle loose-housed dairy cows.

The development of lameness is influenced by a number of different factors (housing, management, human-animal relationship and animal-related parameters). The aim of this study was to investigate the effects of the complex interactions of these aspects and to search for the relative importance of single factors. In 80 dairy herds of Austrian Simmental cows housed in cubicle loose housing in Upper and Lower Austria, risk factors for lameness, selected from the four factor groups housing, management, human-animal relationship and animal-related variables, were investigated during one farm visit in the autumn and winter months. To assess their relative importance, a multivariable analysis (regression trees) was calculated. The most important risk factor for lameness was the lying surface: straw bedding of at least 2 cm thickness or cow-comfort mats were associated with a lower percentage of lame cows. In case of insufficient quality of the lying surface, the next important parameter identified was the position of the neck rail: a neck rail diagonal greater than 1.94 m was associated with a lower percentage of lame cows. By contrast, on farms with high-quality lying surfaces, lameness prevalence was lower when at least parts of the alleys were constructed with solid floor and not slatted. Further variables associated with a low prevalence of lameness were a longer time span between calving and separation of the calf from the dam, the existence of an outside run, a lower percentage of fat cows, a greater space allowance, more cubicles than animals and a lower kerb height. In addition, further management factors such as the way in which heifers are integrated into the herd or management decisions taking into account the cows' welfare were related to less lameness. Human-animal relationship variables such as, for example, the behaviour and attitude of the stockpeople were explaining variables. In sum, important risk factors were found in all factor groups. Therefore it is necessary to optimise all those different aspects mentioned above to reduce the risk of lameness.