THE BLOG

Flatulence In Dogs

19/01/2015 13:47 GMT | Updated 18/03/2015 09:59 GMT

Against my better judgement, I sometimes sneak my dogs a treat that doesn't quiet fit into the diet of healthy canine nutrition. Rest assured, I will pay the price later when it smells like something died in my house.

Farting dogs can be funny and for some gas isn't a big deal, but for others the smell can be so foul you need a peg on your nose while around your dog.

While gas is normal from time to time, it is not normal for gas to occur all the time. Sadly, many owners have accepted their chronic gassy canines as just the way they are. We tend not to question the things we have already accepted as normal, but what if we did?

Most cases of gas are not very serious and can be effectively treated with changes in diet, adjustments in feeding behaviour and proper exercise.

That said, if your dog's gas is associated with vomiting or chronic diarrhoea, if he shows symptoms of pain, a hunched posture, restlessness, or lies down in a "praying" position, take him to see a veterinarian right away.

It goes by many names

There are many different terms used to describe the release of gas from the body. The medical term is flatus and is defined as "gas expelled through the anus".

I haven't been able to find any studies of rectal gas excretion rates in dogs but in people they range from 400 to 1500 ml/day. People eating their usual foods pass gas per rectum an average of eight to ten times per day with an upper normal limit of 20 times per day.

Where does the gas come from?

The most common cause of excessive gas in dogs is diet. The odd fart can happen from eating something new but most cases of chronic gas are likely to be caused by food that is poorly digested. This can cause excessive fermentation in the small intestine and subsequent formation of gas.

Foods that contain large amounts of non-absorbable oligosaccharides are likely to produce large amounts of intestinal gas. This is because dogs lack the digestive enzymes needed to split these sugars into absorbable monosaccharides, causing bacteria in the large intestine to ferment these sugars, producing carbon dioxide and hydrogen gas.

Soy beans, peas, beans, milk products, high-fat diets and spicy foods are all commonly associated with flatulence and GI upset in dogs.

When your dog swallows food or water, he also swallows small amounts of air which collect in the digestive system. Your dog gets rid of the build-up of air by farting or burping.

Swallowing air is often found with flat-faced breeds such as Pugs, Boxers, Bull Mastiffs and Boston Terriers. Working and sporting dogs and "fast eaters" are also at higher risk of swallowing air.

In people, air introduced into the stomach can result in flatus within 15 to 35 minutes and it has been estimated that gases can move 10cm a second through the GI tract.

The stinky fart

Farts are composed of 99% of odourless gases. The remaining 1% is composed of odoriferous gases that contain sulphur. The more sulphur-rich the diet, the more sulphides are produced by the bacteria in the gut and the more the farts will stink.

Nuts, spices, cruciferous vegetables (broccoli, cabbage, cauliflower, Brussels sprouts) and high protein ingredients often increase the production of smelly gases.

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Silent but deadly

When humans fart, vibrations of the anal opening produce the sounds. These sounds depend on the speed of ejection of the gas and the tightness of the sphincter muscle of the anus.

Most dog farts are silent or rarely more than a little "poof". One explanation could be down to anatomy. Your dog's digestive system is horizontal which puts less pressure on the anal opening, thus the gas is expelled more slowly.

Another theory suggests it is because dogs don't feel embarrassed about farting, so the sphincter is more relaxed, leading to less noisy farts.

How can you reduce your dog's flatus?

Feeding a consistent and healthy diet is the best way to reduce your dog's flatulence. As discussed above, certain protein, carbohydrate and fibre ingredients may affect gas production.

In humans, a study was done feeding a diet with half the calories coming from pork and half from baked beans. The diet increased flatus elimination from 15 to a whopping 176ml/hour.

Highly digestible foods reduce the residues available for bacterial fermentation in the large intestine and therefore foods with high digestibility should be fed.

Certain carbohydrates can affect gas production. Changing the source of carbohydrates in the food may benefit some dogs. Studies have shown that foods containing rice as a carbohydrate source result in less intestinal gas formation than foods containing wheat or corn.

Because protein is high in sulphur, changing the source of protein in your dog's food may affect the odour of your dog's gas. Leguminous protein sources such as soy bean meal should be avoided in dogs.

Soluble and fermentable fibre-enhanced foods may contribute to excessive gas. Even some mixed fibres in adequate amounts (bran, soy fibre, soy hulls, pea fibre and beet pulp) can be a source of flatulence.

Bottom line (no pun indented)

  • To avoid aerophagia (excessive air swallowing), feed several small meals a day and discourage rapid eating by using a slow feeder. A cupcake pan can be useful as food can be split into the separate holes.
  • Changing the source of protein or carbohydrate in the food may benefit some dogs. For example, changing from a food that contains corn, chicken meal and soy bean meal to a food that contains lamb meal, rice and barley may be helpful.
  • Feed a highly digestible food. Avoid low-quality proteins (usually of plant origin) and foods containing ingredients from legumes such as soy beans peas, peanuts and lentils.
  • Vegetarian based foods can be problematic because they often include potentially odoriferous sulphur-containing vegetables and legumes.
  • Avoid foods or treats containing lactose, especially in dogs with lactase deficiency or with underlying GI disease.
  • Know your dog's allergies and food sensitivities, and steer clear of foods that will irritate his stomach.
  • To eliminate bad smells, change the dietary protein source and decrease dietary protein levels. Avoid nuts, spices and cruciferous vegetables (broccoli, cauliflower, Brussels sprouts and cabbage).