Housing System, Milk Production, and Zero-Grazing Effects on Lameness and Leg Injury in Dairy Cows

The aim of this study was to assess the effect of grazing (G) vs. zero-grazing (ZG), level of milk production,and quality and type of housing system [free stalls (FS)and straw yards (SY)] on the prevalence of lamenessand leg injuries in dairy cows. Observations were madeon 37 commercial dairy farms across Great Britain. Asingle visit of 5 d duration was made to each farm.During this visit, lameness scores and the incidence ofswellings, rubs, and injuries to hocks and knees wererecorded on all the peak- or mid-lactation cows. Aspectsof the quality of housing and management that werelikely to affect foot and leg health were recorded. Therewere more lame cows on ZG farms (39 ± 0.02%) thanon grazing (G) farms (15 ± 0.01%), and lameness scoreswere higher on FS farms compared with SY farms (0.25± 0.01 vs. 0.05 ± 0.01). Cows on SY farms had fewerhock and knee injuries compared with FS farms. The frequency of knee swellings was higher on ZG farms(0.31 ± 0.02) than on G farms (0.15 ± 0.01). Aspects of the free-stall design affected foot and leg health. The number of hock swellings increased with increasing stall gradient (0.16 ± 0.01 with no slope vs. 0.39 ± 0.02at a 0 to 1.5% slope). There was an interaction between the length of the free-stall lunging space and the hip width of the cow, indicating that the incidence of lameness is generally highest on farms with small free stalls and heavy cows. High levels of milk production did not affect lameness or leg injury. The results indicate that housing cows throughout the year potentially has adetrimental effect on foot and leg health. However, good free-stall design may reduce lameness and leg lesions