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Is it a dog or a cow?

Sunday, February 8, 2015
Your Pet & You

Dogs often engage in a common behaviour that makes their owners wonder if the dog is sick: grass eating.

While most experts agree that a dog eating grass is not a cause for concern, owners still struggle to understand why dogs eat grass. The next two articles will look at the most common theories of this cow-like behaviour.

When we delve into the history of domestic dogs, we discover that dogs are the descendents of wolves and they thus started off as predators—hunters who would eat the entire prey animal including meat, bones, organs and stomach contents. The stomachs of herbivores who fell prey to the wolves would have included vegetation, and this greenery combined with the protein of the dead animal made up a well-balanced diet.

With the advent of agriculture and the formation of villages, wolves formed loose associations with our human ancestors and they learned that scavenging from our village dumps and latrines was a far easier way of obtaining food. For the past 12,000 years of canine domestication from wolves to dogs, these opportunistic scavengers have devoured anything and everything, as long as it fulfilled their basic dietary requirements. To this day, wolves and wild dogs continue to eat plant matter such as fruiting plants, fruits, berries and other vegetation; but the most commonly consumed plant is grass. It is widely acknowledged that dogs are therefore not carnivores but are considered to be omnivores of a certain type. Nowadays dogs do not hunt for their food but they still possess the natural scavenging instinct that includes eating vegetation as an alternative food source.

Pica is the technical term for the disorder characterised by eating items that are not food or are not edible. Humans are known to eat dirt, rocks, paper, chalk, make up—even deodorant! It is thought that this behaviour in humans is as a result of a nutritional deficiency and researchers believe the same could be true for dogs who eat grass. Eating grass may be a way to supplement the dog’s body with any missing nutrients, vitamins and minerals in the diet. Grass also provides roughage which dogs need in order to digest and excrete waste products efficiently. If you suspect that your dog is eating grass because of a dietary imbalance or to improve digestion, the simple solution is to switch to a food with high fibre content or to add supplementary nutrients and fibre to your dog’s diet by including raw or lightly cooked vegetables in his meal.

One of the more common theories bandied about by the average layperson is dogs eat grass because they are sick and this behaviour helps to purge their systems through vomiting. Like humans, dogs can suffer from gastrointestinal issues including upset stomach, nausea, bloating, and illness from pathogenic microbes and like humans, vomiting can bring relief. 

However, the majority of research in this field finds that in most cases dogs do not display signs of being ill before eating grass, and that most of the dogs who ate grass did not vomit after doing so. Of interest is that the method of eating grass varies in dogs—researchers found that dogs that ate grass slowly or nibbled rarely vomited afterwards, while those dogs that ate grass rapidly or gulped almost always vomited. It seems that when grass is gulped down rather than chewed, the grass blade tickles the throat and stomach lining. This sensation in turn may cause the dog to vomit. It is therefore believed that dogs who eat grass as a means to vomit are not regular grass-eaters and when they do eat grass, it is a rapid feeding that almost immediately results in vomiting to relieve stomach discomfort or distress.

Some people have proposed that dogs eat grass to treat intestinal worms but there is currently no scientific evidence to prove this. Instead, the scary truth is that the eggs and larvae of intestinal worms such as hookworms are shed through faeces and if owners do not thoroughly clean their yards and pick up any poop, these parasites can remain on the grass and in the environment. When grass contaminated with faecal material is consumed by the dog, the parasite makes its way to the dog’s intestinal tract causing an active infection. A regime of cleaning the dog’s environment and regular de-worming for your dog is therefore highly recommended.

• Moving away from physical theories, we will explore the psychological theories in the next article.

Copyright © Kristel-Marie Ramnath 2015. For further information contact 689-8113 or [email protected] ​​



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