Written by Krista Vernaleken, VMD
Why do dogs eat grass? Because they like it.
This is one of the more common and difficult questions that vets get, simply because there isn’t really a good, satisfying answer.
Back when dogs were wolves, they would have a varied diet containing meat, bones, and the intestinal contents of their prey. What’s in the intestines? Grass and other plant material. Current formulated diets do contain the nutrients that their wild counterparts obtain from eating prey, but could there still remain some evolutionary desire to eat some grass and plant materials? Some vets think so.
Some dogs eat grass when they have a stomach ache. Then some of them vomit. Does the grass make them vomit? Or were they going to vomit anyway? Or did they feel a little nauseous and vomit just because they ate something (whether it was grass, water, or food, they would have vomited when that item hit their stomach).
Any time I am asked about grass eating, my big question is, “Is this something she’s always done, or did it start recently?” If the pet has always done it, then they eat grass because they like it (a.k.a. it’s behavioral). When it’s new, there is occasionally a primary reason such as parasites, nutritional deficiencies, or some gastrointestinal disease. More often than not, there is no answer to be found.
Don’t count on being able to ditch the lawn service, though…they’re not sheep!