29 February 2008

4 minute read

When you see your cattle rubbing themselves against water bowls, walls or fences, they are just doing what comes naturally. Grooming is a daily ritual for many farm animals and dairy cows are no exception.

About 20 years ago, dairy equipment manufacturers introduced mechanical brush-on-demand devices that help cows groom themselves. Since then, many new free-stall dairy barns have included mechanical brushes as part of the installed equipment.

Cow brushes have been reported to be an environmental enrichment for cattle. They could improve overall cow comfort and help reduce boredom in the barn.

Various types of brushes are available but their basic features are similar. A cow rubbing against one of these devices activates the rotation of the brush, powered by an electric motor. When the animal is finished, the unit turns itself off.

Recent research in British Columbia evaluated how a mechanical brush affects the grooming behaviour of group-housed dairy cows. Researchers split a 72-cow herd into groups; each spent time during a control period without a brush and an experimental period with it. Using video surveillance cameras, researchers evaluated each animal's behaviour.

During the control period, cows scratched themselves mostly on walls and water bowls. Each animal groomed herself an average of three times a day for a total of about one and a half minutes.

Within the first day of access to the mechanical brush, more than half the cows were using it during the experimental period. After a week, most of the cows were getting themselves brushed. These cows cut the time in half that they would spend grooming on walls or water bowls but the time spent at the brush more than compensated. Each cow averaged almost seven minutes a day using the device.

Total scratching time for cows when they had access to the mechanical brush was more than six times greater than when they were without it, and the number of times they groomed themselves more than tripled. These findings suggest the mechanical brush allows the cows to express and better satisfy their need for regular, daily grooming.

Introducing a mechanical brush to the pen not only increased the time and frequency of grooming but also changed the parts of their bodies the cows scratched. Head scratching accounted for 86 per cent of the total, with neck and thigh at 11 and three per cent, respectively during the control period. When the mechanical brush was available, the proportions changed. Although the head remained the main target 63 per cent of the time, the cows used the brush to scratch hard-to-reach places like their backs and tails 10 and nine per cent of the time, respectively.

Although cow cleanliness was not recorded during this trial, farm personnel involved with the project reported that cows appeared much cleaner when they had access to the brush.

In an earlier study in the Netherlands, researchers reported that animals with access to a cow brush had cleaner coats that were also in better condition. As well, behaviour of these cows indicated less discomfort and frustration from itchiness compared to those without access to the cow brush.

These differences increased with time-a positive aspect that may encourage you to consider installing one of these devices in your barn.

Position brushes to optimize cow traffic.

If you decide to install a cow brush in your free-stall barn, careful positioning is a must to optimize cow traffic as well as brush use. In exercise yards, limited time spent in the yard by the cows may increase competition for the brush. You may need more than one unit, depending on herd size.

Ensure cows have excellent footing under the brush, even to the point of roughening the floor more than usual. Cows can contort themselves into some pretty strange positions trying to scratch hard-to-reach places. They have been known to fall and injure themselves in the process if the floor is slippery.

Don't place brushes within eight feet of a water tank or along the feed manger. There will be lots of hair and dust dispersed in the area immediately around the brush and you don't want it to spoil water or feed quality.

Don't place the brushes in high traffic areas. They will definitely attract additional cows to an area and block normal animal movement. A crossover alley between the free stalls is usually the best choice. If it's at the end of the barn and there is no water trough nearby, placing the brush on the end wall will keep it out of the line of traffic. If there is a water tank, the inside of the turn may be the only option.

In either case, a wider crossover of 16 to 20 feet is advised if you intend to provide a place for drinking and grooming as well as normal cow movement.

It has been demonstrated that dairy cows tend to increase their grooming behaviour following periods of restraint-grooming seems to be one of the first behaviours a cow does after being freed. It has been suggested that mechanical brushes could also be a desirable addition for exercise yards in tie-stall operations.

Reference:

Usage of Mechanical Brushes by Lactating Dairy Cows DeVries et al. Journal of Dairy Science. 2007; 90: 2241-2245.

This article first appeared in the Ruminations column of The Milk Producer Magazine, July, 2007.

November 2007