Moncada, A. C., Neave, H. W., von Keyserlingk, M. A. G. et al. 2020. Use of a mechanical brush by dairy cows with chorioptic mange. Applied Animal Behaviour Science 223, 104925.

Mechanical brushes allow cows to groom. Mange is common in indoor-housed cattle, and this affliction may affect cow motivation to use a mechanical brush. The aim of this study was to assess changes in dairy cow motivation to use a brush in relation to signs of mange, and before and after the application of an anti-parasitic drug. Four groups, each consisting of 12 mid-lactation cows with different scores of mange severity, were allowed to access a mechanical brush by pushing a weighted gate. The number of times cows pushed open the gate to access the brush, and the duration and frequency of brush use, were used as response variables. Measurements were taken 9 d before treatment with an anti-parasitic drug, the initial 9 d after treatment, and then again for a second 9 d Post-treatment period. During each period, the weight required to push open the gate was increased every 3 d in 9 kg increments to a maximum of 27 kg. The severity of mange did not affect outcome variables. Brush use was highest when 18 kg was set on the weighted gate during Pre-treatment, and declined when weight was increased to 27 kg. During the second Post-treatment period, brush use remained at a lower level (averaging 9.1 ± 1.6 min/d) across all weights. These results indicate that brush use in mange-affected cows decreases after initial usage, potentially due to elimination of mange, and that regardless of the severity of mange, access to a grooming device is a valuable resource for dairy cows. Further work is required to understand how motivation to access a brush changes during the mange healing process.