Health and welfare of dairy cows in different husbandry systems in Switzerland.

Our objective was to compare health and welfare of dairy cows kept in three types of husbandry systems: (1) tie stalls with regular exercise in summer but minimal outdoor access during winter (the reference level for analyses); (2) tie stalls with regular exercise in an exercise yard or pasture throughout the year; (3) loose-housing with regular access to an outdoor exercise yard or pasture. A total of 134 farms were visited (two to) three times in two years. Cows were examined for lameness, skin alterations at the hock joints, scars or injuries at the teats, and skin injuries at other locations. Lying and standing-up behavior were also evaluated. Farmers were requested to record the incidence of medical treatments for the whole observation period. A multivariable logistic-regression analysis was performed for each indicator of health and welfare with husbandry type, aspects of the housing system, farm characteristics, and management routines as the predictor variables. For welfare indicators recorded on individual animals, regression was performed correcting for clustering of observations within herds by Generalized Estimation Equation. Risk factors for the incidence of medical treatments were analyzed in a negative-binomial regression model. The odds for lameness were reduced for tie stalls with regular exercise throughout the year (OR=0.7). The prevalence of alterations at the hock joints was lower in loose-housing with regular outdoor exercise (OR=0.4). Teat injuries were less frequent in loose-housing with regular outdoor exercise (OR=0.1) and tie stalls with regular exercise (OR=0.4). Farms with loose-housing and regular outdoor exercise had a lower incidence of medical treatments (IR=0.6) than reference level farms.