Tuesday, January 12, 2021 - We humans will do just about anything to scratch an itch that's in a hard-to-reach spot. We've made backscratchers, we'll rub up against thresholds, just about anything to feel that "Aaaahhh, that's the spot!" moment.

Cows, it turns out, aren't much different, according to a study published in the journal, Biology Letters. In fact, cows will do almost as much to seek out grooming options that provide a sense of relief as they will to gain access to fresh food.

Cows can groom by licking themselves and each other. Their tongues, however, cannot reach all the right places, so they turn to other options, like tree bark or other rough surfaces. This process provides them with a way to remove parasites and other undesirable materials from their skin and fur.

If these natural surfaces aren't available, they may turn to whatever surface best scratches the itch. This can cause damage to the barn, which means money must be spent on repairs. One way to alleviate that potential destruction is by supplying the cows with access to a mechanical brush. The device basically looks like a brush in a car wash. When a cow steps close to the brush, or rubs up against it, the brush begins to whirl, providing the cow with a way to groom.

Cows seem to enjoy having access to such brushes. According to the study, cows with access to such brushes are cleaner and spend about fivefold more time grooming than barn cows without access to such brushes. This, the researchers suggest, signifies the importance of the brushes to the cow.

Researchers from the University of British Columbia (UBC) decided to test just how important access to these brushes were to cows. Ten healthy pregnant cows were given a few days to get used to an experimental pen and a brush. They were also trained to open a 15-pound (7 kilogram) weighted push gate, and they had to eventually be able to do so without a trainer present. The gate restricted access to either an empty space, a space with a mechanical brush or a space with fresh feed. Weight was added to the gate each day it was used until none of the cows could open it. This was done in order to determine how much effort a cow would exert to gain access to a certain area.

Cows were willing to push almost the same amount of weight to access fresh feed as they were to gain access to a mechanical brush. They were, no surprise, less interested in pushing their way into an empty space.

"The way I see a cow move under that brush goes way beyond just relieving that itch," Temple Grandin, a researcher at Colorado State University, known for her work on farm animal behavior and welfare, told The New York Times.

Access to these brushes are required by law in Denmark, but they're entirely optional in Canada and the U.S. One of the UBC researchers, Marina von Keyserlingk, suggested to The Times that giving cows access to the brushes could make them happier, which in turn could make consumers of cow-based products happier, knowing that the cows were happy.

DOC’S COMMENT:  A low-tech way to accomplish the same thing is to manually brush each cow daily with a stiff bristle brush.  In addition to the grooming effect, this procedure also allows the astute handler to evaluate the health of the animal by its reaction to stimulation of the acupuncture points.

For more information, and photos of these brushes in action, visit this link: https://www.mnn.com/earth-matters/animals/stories/cows-mechanical-scratcher-study