Can environmental variables replace some animal-based parameters in welfare assessment of dairy cows?

Animal-related parameters best fulfil the requirements of a valid welfare assessment, but often they are less feasible than other parameters. Therefore, this paper examines whether animal-based parameters are connected with each other and with environmental factors in order to find out if some can be discarded without loss of information. Eighty Austrian dairy herds (21-55 Simmental cows) housed in loose-housing cubicles were visited. Housing, management and the human-animal relationship were assessed. Animal-based parameters such as lameness, skin lesions and social behaviour were recorded. For the statistical analysis, Spearman correlation coefficients and regression trees with additional cross-validations for the assessment of the predictive performance of models were calculated. The animal-based parameters could be explained by environmental variables only around 213 (goodness of fit). The calculated regression trees explained 62% of the percentage of lame animals, 58% of leg injuries on the carpal joints and 69% of the agonistic interactions. Leg injuries on the tarsal joints could be explained to quite a high degree (77%). Cross-validated regression trees, however, which are more significant for prediction on forms in excess of this study, accounted for 31% of the total variance of lameness, 44% of the leg injuries on the tarsal joints, 33% on the carpal joints and 25% of the agonistic interactions. Only a few correlations between animal-related parameters were found: lameness was correlated with leg injuries on the tarsal joints and on the carpal joints. Leg injuries were correlated with each other. Due to the lack of interrelations between animal-related parameters and the moderate prediction by environmental factors, we do not suggest replacing the investigated animal-related parameters for on-farm welfare assessment in dairy cattle.