Short communication: Usage of mechanical brushes by lactating dairy cows.

The objective of this experiment was to investigate how the provision of a mechanical brush affects the grooming (scratching) behavior of group-housed dairy cattle. To do this, we compared the grooming behavior of 72 dairy cows, split into 6 groups of 12, in the absence of a brush (control) and when provided with a mechanical brush (experimental). We analyzed the duration and frequency of scratching on pen objects (wall and water trough) and on the mechanical brush between the control and experimental treatments. Further, we compared the relative frequency of scratching on parts of the cow's body (head, neck, back, tail, and thigh) between the control and experimental treatments. Within 24 h of installation of the mechanical brush, 56.9% of the cows utilized the brush. Within 7 d, 93.0% of cows used the brush, and by the end of the treatment period, all but one of the cows had used the brush. When the mechanical brush was added to the pen, cows dramatically increased the total time spent scratching by 508% and the frequency of scratching events by 226%. These increases were primarily driven by use of the mechanical brush, which accounted for 91.1% of total scratching time and 79.8% of scratching events. When cows were provided with the mechanical brush, they decreased the frequency of scratching their heads, increased the frequency of scratching on their necks, backs, and tails, and tended to decrease the frequency of scratching their thighs. In conclusion, the results of this study show that the use of a mechanical brush makes it easier for cows to groom themselves, particularly in places that are hard to reach by the cow. This may help satisfy this natural behavior and keep them clean, as well as possibly reducing frustration or stress due to boredom when housed in freestall barns.