Grooming helps animals remove dirt, parasites and other contaminants from skin and hair & may positively influence the animals’ affective state; cows spend about fivefold more time grooming compared with when brushes are not available

Emilie McConnachie, Anne Marieke C. Smid, Alexander J. Thompson, Daniel M. Weary, Marek A. Gaworski, Marina A. G. von Keyserlingk: Cows are highly motivated to access a grooming substrate, Biology Letters (2018). DOI: 10.1098/rsbl.2018.0303

Abstract: In natural environments, cattle use trees and other abrasive surfaces to scratch and groom themselves. Modern indoor dairy cattle housing systems often lack appropriate grooming substrates, restricting the animals' ability to groom. We assessed the motivation of dairy cows to access an automated mechanical brush, a grooming resource that can be implemented in indoor cattle housing systems. Cows were trained to push a weighted gate to access either fresh feed (positive control), a mechanical brush or the same space without a brush (negative control). Weight on the gate was gradually increased until all cows failed to open it. The weight each cow was willing to push to access each resource was assessed using the Kaplan–Meier survival analysis. Despite differences in methodology used to obtain data on motivation to access feed and the brush, the outcomes were very similar; cows worked as hard for access to fresh feed and the brush (p = 0.94) and less hard for access to the empty space (compared with fresh feed: p < 0.01; brush: p < 0.02). These results indicate that cows are highly motivated to access a mechanical brush and that it is an important resource for cows.