Why do Dogs Eat Poop?
Laurie Anne Walden, DVM
Revolting as it seems to us, some dogs like to eat feces. If you’ve been the not-so-proud owner of a poop-eating dog, you’ve probably wondered why dogs have such a nasty habit and what you can do to stop it. Unfortunately, the short answers are (1) because they’re dogs and (2) not much.
Mother dogs ingest their puppies’ feces during cleaning, but that’s not the only time dogs eat stool. The scientific word for eating feces is coprophagy, and some dogs seem particularly enthusiastic about it.
Coprophagy in dogs hasn’t been extensively studied, but researchers from the University of California, Davis, School of Veterinary Medicine recently published the results of a new investigation of canine coprophagy. They focused only on dogs that eat dog feces (not the feces of other species, like cats or horses). The investigators conducted 2 online surveys of dog owners and received over 3000 responses.
According to their results, 16% to 23% of dogs engage in coprophagy (depending on how strictly coprophagy is defined—that is, how many times a dog has to eat poop to be classified as a poop eater). Most coprophagic dogs in the study preferred fresh stool no more than 2 days old. Age, sex, neuter/spay status, and diet were not associated with coprophagy. Dogs that were hard to housetrain (and therefore might not mind being in close contact with feces) were no more likely to eat feces than were dogs easy to housetrain. Compulsive or anxious behavior was also not related to stool eating. These results may not be definitive, though; in a study published in 2010, anxiety disorders and neutering (in male dogs) were both associated with coprophagy.
The researchers did turn up a few other factors linked to poop eating. Coprophagic dogs were more likely than noncoprophagic dogs to be described as “greedy eaters.” Terriers and hounds were more likely than other breed groups to be stool eaters (although in the 2010 study, sporting dogs had this dubious honor). The data did not allow for extensive analysis of specific breeds, but among the breeds that could be studied, the percentage of stool eaters was highest in Shetland sheepdogs and lowest in toy, miniature, and standard poodles. Not surprisingly, dogs in multiple-dog households (with access to more stool sources) and dogs reported to eat cat poop or dirt were more likely than others to eat dog feces.
The investigators asked survey participants about methods they used to (try to) control their dogs’ coprophagy. Reported methods ranged from behavior modification/management techniques (the most common of which was chasing the dog away from the poop) to various food additives. The success rates of all of these methods were abysmal. The highest success rate, only 4%, was with a reward-based “leave it alone” command. Everything else had success rates ranging from 0% to 2%. The authors were careful to point out that their data came from self-reported dog owner surveys. Clinical trials, if someone were to conduct them, might yield different results.
So is poop eating really a problem for dogs? It depends. A healthy dog who eats the stool of another healthy dog probably won’t have much trouble, although some types of fecal bacteria are hazardous if ingested. Parasite transmission is likely the biggest risk. Many intestinal parasites (like hookworms and roundworms) are spread through fecal-oral contact. And a couple of case reports have described dogs that developed drug toxicosis from eating the stools of housemate dogs that were taking medications.[3,4] A veterinary examination is always a good idea for a dog who eats stool, especially if the behavior is new or increasing, in case the dog has a medical reason for coprophagy.
If your dog eats stool, the best way to control it is to limit his access to feces. Picking up stool in the yard is just about the only way to keep a dog from eating it. Before you get angry at your dog or try punishment (which doesn’t work anyway), remember that this behavior is normal for dogs. The UC Davis researchers hypothesized that domestic dogs inherited the coprophagy habit from their wolf ancestors—so if nothing else, your poop-eating canine has lots of company.
1. Hart BL, Hart LA, Thigpen AP, Tran A, Bain MJ. The paradox of canine conspecific coprophagy. Vet Med Sci. 2018;4(2):106-114.
2. Boze BGV. Correlates of coprophagy in the domestic dog (Canis familiaris) as assessed by owner reports. J Appl Companion Anim Behav. 2010;4(1):28-37.
3. Hutchins RG, Messenger KM, Vaden SL. Suspected carprofen toxicosis caused by coprophagia in a dog. J Am Vet Med Assoc. 2013;243(5):709-711.
4. Shadwick SR, Ridgway MD, Kubier A. Thyrotoxicosis in a dog induced by the consumption of feces from a levothyroxine-supplemented housemate. Can Vet J. 2013;54(10):987-989.
Photo by Noel Lopez on Unsplash
Vaccines for Cats
Laurie Anne Walden, DVM
Both indoor and outdoor cats need vaccines. Vaccination protects cats against infectious diseases that cause serious illness or death. This article describes the vaccines that veterinarians commonly recommend for cats.
One factor that affects vaccination protocols for cats—but not dogs—is the risk of injection-site sarcomas. Some cats develop these malignant tumors at the injection sites of vaccines or other substances. These cancers are uncommon (estimated to occur in 1 to 10 of every 10,000 cats vaccinated) but can be devastating. Although the vast majority of cats do not develop injection-site sarcomas, feline vaccination protocols are designed to balance the tumor risk with the need to keep cats protected from infectious disease. Recommendations include giving cats only the vaccines that are necessary, vaccinating cats no more often than necessary, and using vaccine formulations that are less likely to cause sarcomas.
Rabies vaccination is mandated by law for dogs and cats in the United States. In North Carolina, all cats, dogs, and ferrets aged 16 weeks and older must be vaccinated against rabies. Rabies vaccination laws are one reason this fatal disease is very rare in humans in the United States. Around the world, rabies kills tens of thousands of people every year.
Cats in North Carolina can and do get rabies. In 2017, cats were 1 of the 5 most common species to test positive for rabies in this state (after raccoons, skunks, foxes, and bats). The total number is low, but the risk is real.
Cats that live 100% indoors need rabies vaccines too. Cats sometimes escape outside. And sometimes the unexpected happens, like a bat getting into the house. The presence of a bat indoors is considered a rabies exposure unless the bat is caught and tests negative. A cat that is exposed to rabies but does not have a current rabies vaccination is subject to quarantine for up to 6 months. Also, a cat that bites a person must be quarantined for 10 days; cats without current rabies vaccinations typically spend this quarantine at a facility instead of at home. For more information, see the post about NC rabies laws.
In North Carolina, the first rabies vaccine a cat receives lasts for 1 year, and subsequent vaccines can legally be given every 3 years (as long as the vaccine is labeled for 3-year use). If your veterinarian recommends giving your cat a rabies vaccine every year instead of every 3 years, it’s probably because the clinic uses a feline rabies vaccine that is designed to reduce the sarcoma risk and is labeled for 1-year use. Most 3-year rabies vaccines on the market are killed-virus vaccines that contain adjuvants, substances that enhance the immune response. Killed, adjuvanted rabies vaccines have been associated with injection-site sarcomas in cats. A different type of rabies vaccine, a recombinant vaccine, does not contain adjuvants. The most common version of the recombinant rabies vaccine is a 1-year vaccine. Ask your veterinarian which type of rabies vaccine the clinic uses for cats.
Feline herpesvirus 1 (rhinotracheitis), calicivirus, and panleukopenia virus
Vaccines for feline herpesvirus 1, calicivirus, and panleukopenia virus are often included in a single combination vaccine. The American Association of Feline Practitioners (AAFP) recommends that all cats be vaccinated against these viruses as kittens (in a series of boosters), again 1 year later, and then every 3 years. In past decades, cats received these vaccines every year, but annual vaccination is no longer considered necessary.
Feline herpesvirus 1 and calicivirus are 2 of the main causes of feline respiratory disease complex. This illness spreads easily from cat to cat. People can also carry the infectious agents on their clothing, which is how indoor cats can be infected. Infection causes sneezing, discharge from the nose and eyes, conjunctivitis (pinkeye), fever, mouth ulcers, and eye ulcers. Some combination vaccines also cover Chlamydophila (Chlamydia) bacteria, which cause conjunctivitis in cats.
Feline panleukopenia virus is very contagious among cats, and infection can be fatal. The virus is similar to canine parvovirus. Like parvovirus, it destroys cells lining the intestine and impairs immune function. In kittens, it can also damage the part of the brain that regulates coordination and balance.
Feline leukemia virus
Feline leukemia virus is a retrovirus that suppresses immune function and causes cancer. Because the virus impairs immunity, infected cats develop a wide variety of medical problems. Most infected cats die within 3 years of diagnosis. There is currently no cure.
Vaccines against feline leukemia virus have been associated with injection-site sarcomas. For this reason, the decision to vaccinate an adult cat usually depends on the cat’s lifestyle and risk factors. However, the AAFP recommends vaccinating all kittens against feline leukemia virus. A nonadjuvanted recombinant vaccine is available.
Photo by Sticker Mule on Unsplash
Laurie Anne Walden, DVM
The contents of this blog are for information only and should not substitute for advice from a veterinarian who has examined the animal. All blog content is copyrighted by Mallard Creek Animal Hospital and may not be copied, reproduced, transmitted, or distributed without permission.