AP--Animal Production Technology The Role of Finite-element Analysis in Predicting the Injury-reduction Potential of Dairy Cow Cubicle Synthetic Beds

The optimum degree of cushioning in dairy cow cubicle synthetic bed materials is a compromise between impact force attenuation and stability. Farm trials aimed at finding the best materials are expensive but finite-element analysis, a computational method routinely used for engineering stress analysis, is now able to model the deformation of foam-like cubicle bedding materials under loads induced by a kneeling cow. It thus offers the potential for predicting cushioning performance for less cost. This paper compares finite-element analyses of two types of cubicle bed, recycled rubber-crumb mattresses and ethylene vinyl acetate mats, the properties of which were derived from simple laboratory experiments, with results from a two-farm study of cow injury assessments. The bed samples were subject to quasi-static compression tests and their force-displacement responses were measured. Both samples were found to be non-linear elastic, with a response that may be characterized as hyperelastic. While both products would provide sufficient cushioning to reduce severe hock and knee injuries, the rubber-crumb mattress was the more compliant of the two and should result in fewer injuries to the cows. These inferences were substantiated by the two-farm study. This allows a practical `injury prevention performance ratingʹ to be investigated.