Health and welfare of dairy cows in barn- versus pasture-based systems

The aim of the present study was to assess animal welfare in two distinct dairy systems (barn- vs pasture-based) in Switzerland over an entire year. All selected farms operated loose-housing systems and dairy herds had pasture access for at least half of the year. In general, barn-based (BB) systems focus on milk production per cow with a feeding strategy mainly based on a mixed ration of conserved feed and concentrates, whereas pasture-based (PB) systems focus on milk production per hectare of pastureland and a feeding strategy that optimises the use of fresh and conserved grass. Fifteen farms from each system were visited four times during the year to assess clinical health and behavioural indicators. Statistical analyses were conducted using binomial generalised linear mixed-effects models at herd-level to identify differences between systems and visits within a system. One third of assessed clinical health indicators showed a prevalence above 1%. Over all visits, hairless patches (17 vs 8%), lesions (6 vs 1%), hindleg swellings (1 vs 0%), too lean body condition score (30 vs 22%), soiled udders (13 vs 9%), stiff walking (27 vs 7%) and lameness (11 vs 1%) were more prevalent in BB herds than in PB herds. During the pasture period, the prevalence of hairless patches and lesions was lower than during the housing period, while soiled hindquarters declined in BB herds but increased in PB herds. No difference in the prevalence of lameness was found between the pasture and housing period; however, the prevalence of overgrown hooves was lower during the pasture period for both systems. Two-thirds of the cows in both systems had an acceptable body condition score, with no differences found over the four visits. The two systems revealed distinct morning activity patterns, with a higher percentage of BB cows lying down and a lower percentage eating compared to PB cows. Observed social behaviours occurred at low frequencies, with allogrooming being the most frequently recorded behaviour in both systems. The ability to closely approach half of the cows in both systems suggests a positive human-animal relationship, despite PB herds having more pasture access than BB herds. The herd-level respiration rate and Temperature-Humidity-Index revealed a weak-to-moderate relationship across both systems (R² = 0.36 for BB and R² = 0.25 for PB). Results from the present study demonstrate that both dairy systems achieved relatively high animal welfare standards, with relatively minor differences observed between the two contrasting systems.