Q. Why do dogs want to eat grass?
A. The two most common beliefs are that the dog is feeling ill and needs to vomit or they may be suffering from a dietary deficiency.
In order to test these theories veterinarians at the University of California at Davis School of Veterinary Medicine did an internet survey of 1,571 owners of healthy dogs. They were asked various questions about their dogs’ diets and grass-eating habits. It was found that out of the 1,571 dogs, 68 percent of them ate grass daily or weekly. Of that 68 percent, only eight percent had exhibited signs of illness prior to ingesting grass and 22 percent of the dogs vomited after eating plant material. My calculations of this survey is that out of the 1,571 dogs 1,068 eat grass on a regular basis, 235 of those dogs vomited afterward and only 85 of them showed any sign of illness prior to ingesting grass.
The few dogs that did appear ill and vomited after consuming grass may indicate gastrointestinal distress occasionally causes grass eating.
The survey also asked questions about the dogs’ specific diets. There was no indication that the type of food fed, including raw diets, were more prone to grass eating. Nor was there any indication that dogs receiving less fiber ate more grass.
Multi-dog households reported a higher incident rate of dogs ingesting grass, which could indicate it’s a learned behavior that one dog teaches another.
The veterinarians performing the survey concluded that this is a common behavior in normal dogs and has no correlation with illness. Additionally, most dogs do not appear to routinely vomit after the consumption of grass. Scientists believe wild canines generally eat grass to help them purge internal parasites and prevent the parasites from building up in their systems. Because well-kept dogs are usually free of worms, the researchers have hypothesized that grass eating is a trait of modern dogs, and most likely they simply inherited this instinct from their wolf ancestors. More studies are needed, but plant eating likely serves a biological purpose.
In conclusion, though most experts agree grazing itself isn’t harmful and is quite common, one thing to keep in mind is that certain herbicides and pesticides used on lawns may be toxic to your dog if ingested. If this occurs contact your vet immediately for medical treatment.
Sally Salopek is the owner and operator of Attend-A-Pet pet sitting services in northern Door County. She has also worked professionally with animals in health care, pet grooming, training, wildlife rehab and rescue. Send your pet-related questions to her at [email protected].