Thursday, October 13, 2011

Why do so many dogs (and some cats) eat grass?


Transcript from this week's episode of The Web-DVM:

Your beloved canine companion clearly is not a cow, so it may be a bit strange to see him grazing on grass outside. It’s even weirder to see your cat doing this. So why in the world would they do this?

Let’s start with dogs. One bit of misinformation out there maintains that dogs are pure carnivores, meaning that they supposedly subsist predominantly on meat based protein. Realistically, however, dogs are omnivores just like people, in that they thrive ideally with a mixed diet consisting of both plant matter and meat, making the craving of plant matter like grass, not entirely unusual after all. Even their ancient cousin the wolf is omnivorous, engaging in the eating of plant matter with similar acts of grazing on grasses, as well as eating the plant matter out of the guts of their herbivorous prey.

Some dogs only seem to eat grass when they are feeling sick, prompting the owner to schedule to a vet visit because Buffy is repeatedly eating grass and vomiting it back up. Grass, after all, contains fiber which can help to expel worms and provide bulk to relieve diarrhea. Some grasses are rich in the green pigment chlorophyll, a compound that is rich in anti-oxidants and free radical scavengers that help to boost an immune system stressed with illness. Chlorophyll also has antiseptic properties, which could be helpful in cases of bacterial infections of the gut.

Many veterinarians dismiss this notion of dogs craving grass only when they are ill, maintaining that they are just not intelligent enough to know that some elements of certain kinds of grasses may be beneficial during times of GI upset, that their grass eating and GI upset are simply coincidental. I do not happen to be of this opinion.

While I would agree that dogs are not going to be smart enough to seek treatment for GI upset on their own the way we seek ant-acids for indigestion, I believe that on some instinctual level born of evolution, some dogs do indeed engage in the eating of grass only when sick.

For other dogs, the eating of grass is strictly a behavioral phenomenon, done simply out of boredom. This fact is evidenced by the numbers of grass eaters that are less apt to partake in grass grazing after the owner takes more time to play with and engage with the dog.

So what about cats? Interestingly, dietary-wise, cats are quite different from dogs and people in that they actually are true carnivores meaning they can fulfill all of their dietary needs and essential nutrients by eating a 100% meat diet. Given this fact, it seems especially strange that a cat would enjoy grazing on grass, but the truth is that many do. While the common storyline from dog owners is that Buffy only eats grass when he is sick, the same is not heard with nearly the same frequency in cats.

This seems to make the instinctual evolutionary craving for the aforementioned medicinal elements of grass less likely to be the case in cats. Still, since we cannot ask them, it cannot be completely dismissed. More likely, however, cats that tend to graze on grass do so out of boredom.

So what do you do if your dog or cat grazes on grass? Is it a problem? Well, if your dog or kitty is one of those that only seem to eat grass to vomit it up when sick, then perhaps you should schedule a veterinary visit to deal with said illness that prompted the behavior.

For all others that simply seem to enjoy it, try engaging with the pet more to alleviate potential boredom. For dogs, consider more walks, swimming, fetching, or just tickling the tummy as often as possible. For cats, try getting a cat jungle gym in the home, engage in play with cat toys or a laser pointer, or consider getting Tiger a window stand for more visual stimulation.

If in the end, your dog or cat eats grass no matter what you do, it is not likely to cause any harm, in fact, it could even stand to do them some good. The only caveat to this is that many commercial lawn pesticides can cause harm to your dogs and cats if ingested with the grass. As such, for homes of pets that have a tendency to dine on the lawn, it is wise to choose only lawn pest control products that are organic and safe for animal ingestion, or avoid them altogether if possible.

This is Roger Welton reporting, for The Web-DVM.

Dr. Roger Welton is the President and chief veterinarian at Maybeck Animal Hospital in West Melbourne Florida, as well as CEO of the veterinary advice and health management website


Carol said...

Your timing with this info could not be more relevent for me, as my Lab just this morning began grazing on grass and heaving it back up. He is one of those dogs that the "evolutionary instinct" to crave grass when he has tummy trouble. Thanks to you, I now know that for sure. Being the billy goat that he is, it happens all too often. Off to the vet we go! :)

Jordyn said...

I think dogs are very intelligent and I can agree that they would eat grass to show they're not feeling well. They are a amazing.

Robin said...

i have just begun puppy training my little one and he's forever eating grass. i was worried but thanks for putting my mind at ease.

Dr. Larry said...

I've found that if your dog is eating grass, it's not a bad thing (unless it's full of pesticides or something). It shows the dog feels something wrong inside, and they're doing their all to correct it. It's generally just an imbalance in their diet, or they've eaten something which simply "doesn't sit right" and they want to throw it back up. It's when they start not wanting to eat grass, and they're obviously sick that it becomes a problem. That's when you should bring them to see me.

I've owned dogs all my life now (I'm 45, but who's counting?) and I've been a vet for 10 now, I own my own veterinary practice and in all of my experiences, I've had perhaps one or two cases where the dog has had a serious problem and eating grass is the only symptom.

While it can't hurt to check, don't fret too much when your pooch starts. Also, I get a lot of puppies, or young adult dogs eating grass simply because they're bored. That pretty much sums it up. If your dog is eating grass for an extended period (for longer than about a week) then switch up his diet, and (off the record) name brand dog food is often just as bad as the no name brand.

I'm a vet and feed both of my dogs with the no name food, and they're both in perfect health (Maybe a little porky, but I'm not one to judge, haha). Good luck with the pooches. -Larry

Anonymous said...

Finally, someone who has it right! SO MANY (sadly, far to many vets included) are looking for "ONE" reason to explain all grass eating. I will tell you that every time my dog is feeling dizzy from getting a sedative at the vets office he will eat as much of any plant that he can and tries to throw up, then eat more grass, ferns, vines etc... my guess is he's feeling the equivalent of "motion sickness" as my vet said "he's moving his head around like that because he is dizzy, like when you drink too much".. when i drank too much in my college years i certainly wanted to puke to feel better... i used a finger... i'm guessing dogs have a problem putting their finger down their throat... BUT.... my dog also eats a certain plant from time-to-time that he just simply seems to enjoy. is it POSSIBLE that humans try to over simplify dogs??? is it possible that dogs will eat outdoor greens for a variety of reasons??? MIND BLOWING!!!! i know, right?

Anonymous said...

Dogs eat grass because they lack sulphur in the diet. you don't find it in dog can give them sulphur tabs. Dog food isn't all that it should be.

pw1974 said...

Sulphur?? Really?? I have heard alot of "out there" explanations for why dogs eat grass, but that is for sure one I have not yet heard. I thought this video was a very objective and well rounded take on this canine behavior basically offering some plausible reasons while also admitting that some dogs just like it. But I don't recall a sulphur deficiency being mentioned.

Judy said...

The boredome theory seems right on at least for my dog. WHen I am very busy with work and eventswith my human children, my dog grazes like crazy. But when I have more one on one time with him and I can walk him and fetch with him more, the grass eating drops off noticably.

Gail said...

Whether I play with her alot or a little, my dog walks around my yard like she is a cow. I am glad to know that this does not cause any harm because if it did, my Lulu would be in big trouble. She never vomitis up grass and her stools are always normal, just often mixed with undigested grass. I have never used pesticides or fertilizers of my lawn, so I guess there really is nothing to worry about. Thanks for the peace of mind.