Vet advises against feeding grain to wild deer

A post showed up multiple times on my Twitter feed last week. The posted video showed a covered area with a make-shift table surrounded by a herd of deer voraciously munching on the grain strewn across its surface. The text of the original post was positive and to the effect of: ‘I feed them every day like this, isn’t it great?’

To that I would say, “don’t feed the deer.” I won’t deny, it is a pleasant experience to watch wildlife. In fact, there is growing evidence that time spent in nature is essential for our optimum health and well-being. Japanese culture even promotes regular “forest bathing.”

But the wildlife that live in nature are and should remain just that — wild. They have evolved to survive in their particular environmental niche. Since humans already do plenty to disrupt natural processes, we shouldn’t compound the problems by adding supplemental feed.

The first problematic issue with deer feeding is that it brings animals into close contact, which sets up the potential for disease transmission. Deer in nature may share a field, bush and watering hole. But dozens don’t typically aggregate nose-to-nose over a particularly juicy stalk of grass like they do at a pile of grain.

Chronic wasting disease (CWD) can be spread through saliva, urine, feces and contaminated environments, including soil. Bringing animals into one location can facilitate CWD spread. It can also create patches of highly contaminated soil.

Another disease that thrives with deer feeding is tuberculosis. This is the case in Michigan where the bovine strain of tuberculosis bacteria is spread and maintained through feeding practices.

While we don’t have bovine tuberculosis in deer in Canada, there are rare cattle in Canada found to be infected with tuberculosis.

Additionally, there have been infected elk identified in Riding Mountain National Park in Manitoba and bison in Wood Buffalo National Park, which straddles the Alberta-Northwest Territories border.

There is an ongoing risk of the tuberculosis from these areas spilling out into other wildlife and cattle. Feeding deer could enhance the spread should this terrible circumstance occur.

Besides opportunities for infectious disease spread, feeding may harm deer by altering their normal diet. Like cattle, deer are ruminants with a large, intricate multi-chambered stomach, including a rumen. This complex stomach functions as a fermentation vat. It is an essential adaptation that allows deer to digest vast quantities of fibrous plant material.

Just like cattle, deer are susceptible to grain overload. A sudden switch from forage to grain can have deadly consequences. The high carbohydrate levels in grain are rapidly fermented. This changes the type of bacteria that can live in the rumen and leads to acid build-up.

The acid directly damages the lining tissue of the rumen and also draws water away from elsewhere in the body, leading to severe dehydration. Too much acid coupled with dehydration causes the body to go into shock and in severe cases, can cause death.

Another negative consequence of feeding is how it changes the deer’s behaviour. Deer may become accustomed to human interactions, leading to negative or even aggressive encounters during critical times like fawning season.

Feeding may also increase the overall survival of individuals, creating high population numbers that are destructive to crops, gardens and the environment. Excessively high population numbers may also contribute to crowding and disease spread.

Finally, large herds of deer at feeding sites may attract predators, something the individual in the video likely didn’t consider.

While we should enjoy nature and the animals in it, there are many good reasons to keep the lid on the grain barrel.

Dr. Jamie Rothenburger, DVM, MVetSc, PhD, DACVP, is a veterinarian who practices pathology and is an assistant professor at the University of Calgary’s Faculty of Veterinary Medicine.
Twitter: @JRothenburger

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