Wednesday, April 15, 2015

Why do dogs eat poo?

dog litter bags poo bags
Its a yukky subject, but many are asking the question...

Today’s post ventures into some gross territory, but I’ve seen a cluster of clients recently all desperately seeking answers to the following question: why does my dog eat poo?

(Before I go on, please rest assured that I too find this an icky subject and am endeavouring to discuss it with minimal grossness, however if you have a sensitive stomach and this doesn’t apply to your dog, please don’t read on).

It’s a question that veterinary science fails to provide a definitive answer for. Poo-eating, or coprophagia as it is known, is not uncommon in dogs (and it is actually reported as a disorder in some human patients). For many dogs this little habit is a transient phase which appears in puppyhood and disappears as dogs grow up, but for the odd dog it persists.

Why does it happen? Researchers (and there are few with active portfolios in this area, you can imagine why) speculate that it may be due to a dietary deficiency. Experimentally, dogs with severe thiamine (a B vitamin) deficiency will engage in this behaviour, but the key word here is severe.

Chronic exocrine pancreatic insufficiency, or any disease that causes malabsorption, is also associated with this behaviour. Normally these dogs have other signs (weight loss, diarrhoea) and once the disease is treated the behaviour disappears.

Environmental stress, boredom and attention seeking have also been suggested as possible triggers.

Is eating poo harmful? The consensus from the literature has generally been no, but some recent papers have questioned that assurance. There remains no evidence that your dog eating its own stool is a major health risk for your dog. That said, at least one publication suggested that the amount of disgust this disgusting but generally harmless habit produces in owners can be strong enough to sever the human animal bond and result in euthanasia. In which case it’s a major risk.

But eating someone else’s stool can be a health risk to dogs. For example, if that someone else happens to have a bacterial, parasitic or other infectious disease that is transmitted via oro-faecal contact then yes, it can make them ill.
One risk I admit I never considered, until purveying the literature, is the risk of ingestion of second-hand drugs.

In one case report in the Canadian Veterinary Journal, a 9-year-old Golden retriever became hyperthyroid after eating poo from the other dog in the household who was been treated for an underactive thyroid. Not before being through a whole lot of tests first. No one thought to ask – and the owner didn’t volunteer – whether the dog had a poo-eating habit.

In another case published in the Journal of the American Veterinary Medical Association, a 1-year-old crossbreed developed transient signs of renal insufficiency (urinary incontinence, drinking a lot, peeing a lot, dilute urine) and increased liver enzymes after swallowing stool from a housemate who was on non-steroidal anti-inflammatory drugs (carprofen).

(I saw one dramatic example of this, the details of which I won’t go into as apparently my referral letter made the specialist want to throw up, but suffice to say that secondary ingestion of stool containing an illicit drug lead to bizarre – fortunately transient – neurological signs in two French bulldogs).

In both of the published case reports, the clinical signs resolved once owners cleaned up the yards and made sure there was no poo left around.

The lesson here is that if you have a dog with this habit, you need to be particularly cautious if other dogs in the household are sick or on medication.

So what can we do about it?
  1. The first step is to prevent all access to faeces (a step I’ll admit I thought was easy until I met a dog last week who can actually circumvent this process with extreme flexibility. I’m going to leave that description right there).
  2. Do not panic, wave your arms about, scream or become overly animated when you see your dog do this – no matter how grossed out you feel on the inside. You might inadvertently reinforce this behaviour.
  3. Ensure there is no medical reason. Ask your veterinarian to perform a physical examination. Adjunctive tests include blood tests and faecal analysis. Dogs with exocrine pancreatic insufficiency should have their diet supplemented with pancreatic enzymes.
  4. Eliminate boredom. Make sure your dog is exercised at least daily (preferably twice) – this also gives dogs a chance to toilet outside. Provide environmental enrichment such as Kongs and chew toys.
  5. Feed foods that taste bad after digestion – pineapple is said to work a treat but I’ve heard mixed reports.
  6. Adjust the diet. Diets high in carbs may enhance coprophagic tendencies so foods higher in protein are preferable. You can try supplementing a diet. There is a product called Wild Forage which is used for this. It’s made by Ausrichter from a biological peat extracted from moors in upper Austria.


References

Hutchins RG, Messenger KM and Vaden SL (2013) Suspected carprofen toxicoses caused by coprophagia in a dog. Journal of the American Veterinary Association 243(5):709-711.

McKeown D, Luescher A and Machum M (1988) Coprophagia: food for thought. Canadian Veterinary Journal 29:849-850.


Shadwick SR, Ridgway MD and Kubier A (2013) Thyrotoxicosis in a dog induced by the consumption of faeces from a levothyroxine-supplemented housemate. Canadian Veterinary Journal 54:987-989.

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