Physiologic Urge or Taste Preference: Why Do Dogs Eat Grass?
Why does my dog eat grass? I commonly get this question in my clinical practice, for which there are multiple answers. First, it is normal for a dog to eat grass. Second, dogs do so for a variety of reasons, with each possibility needing consideration when intellectually exploring the reasons one’s canine companion has a fondness for forage.
Induction of Emesis
Plant material is highly composed of insoluble fiber that is not readily digestible and irritates/inflames the stomach wall. Blades of grass (both large and small) often accumulate in the stomach instead of appropriately moving into the small intestine.
When a particular degree of inflammation is achieved post-grass consumption, vomit ensues. Underlying illness, including Inflammatory Bowel Disease (IBD), gastrointestinal parasite infestation, metabolic disease (affecting the kidneys, liver, pancreas, etc.), or pica (see below) can stimulate the physiologic urge to vomit. Therefore, dogs can eat grass as a means of facilitating their own vomiting and for reducing nausea.
Grass eating is a behavior exhibited by wolves and the domesticated dog (Canis familiaris). An article in the Journal of Veterinary Behavior suggests that the grass eating traits of a nursing mother can influence similar behavior in her puppies. Your dog’s mother, grandmother, and so on may be partly responsible for imparting modern-day grass eating tendencies.
Lack of stimulation during confinement in a particular environment, such as the back yard, can motivate a dog to eat grass or other various environmental substances. This condition, termed pica, is symptomized by the consumption of non-nutritive material. Pica leads to vomiting, diarrhea, and intestinal obstruction or perforation. This undesirable behavior can be reduced by providing a pet with behaviorally stimulating and appropriate chew toys, companionship, or (as a last resort) a cage-style muzzle.
Pica can be caused by underlying medical abnormalities, therefore veterinary examination, laboratory testing (blood/urine/fecal tests, radiographs, etc.) and dietary evaluation should be explored.
Veterinary behaviorists and nutritionists speculate that dogs eat grass to compensate for nutritional deficiencies. Many of my clients achieve success in reducing their dogs’ grazing by adding fresh greens and/or fibrous vegetables or fruits to the dogs’ diets. Spinach, kale, broccoli, parsley and pineapple have all yielded favorable results. Vegetables are most palatable and digestible when steamed and pureed or finely chopped before being incorporated into a dog’s meal. Additionally, dogs that eat a diet based in whole foods instead of commercially available, processed, non whole-food based dry (kibble) or canned foods tend to exhibit less foraging behavior.
As a dog owner, I discourage my dog’s regular consumption of grass. Fortunately, the occasions when Cardiff eats grass are rare. I theorize that it is because his human grade, whole food diet contains fresh vegetables and fruit (along with muscle meats, grains, etc). Additionally, Cardiff gets plenty of stimulating activity and is not permitted access to nor is confined to areas where boredom may lead to foraging.
As a veterinarian, I see grass eating dogs inadvertently ingesting toxins such as fertilizer, pesticide and other unhealthy environmental debris. Therefore, I recommend dog owners take appropriate measures to deter grass consumption during all stages of life and explore the underlying causes if their canine companions’ motivations supersede human preventative attempts.
Cardiff in Mondo Grass
Dr. Patrick Mahaney