It's The Dog, I Swear

Ranger, an elderly black lab, lay obediently on his right side on the ultrasound table while I performed the abdominal scan. The room was quiet and dark but for a soft glow from the ultrasound screen. Ranger’s owner was at his head end, stroking him, and a tech was beside the owner, gently holding Ranger’s legs, although he was so calm that it probably wasn’t necessary. Then it hit. A wave of intense odour suddenly filled the room. It was incredibly pungent and impossible to ignore. It was as if someone had, inexplicably it must be said, carefully inserted something dead and rancid into each of my nostrils.  

            “It’s the dog, I swear!” the owner said, laughing. Ranger had, as the polite phrase puts it, “broken wind”. Had he ever. We all did loud stage coughs and in the semi-dark I could see the tech waving a hand in front of her face, trying to dispel the cloud. She was closest to the source.

            Who among us dog people does not recognize this scenario? Who has not hastened to point at the dog when heads turn and noses wrinkle? To be fair, it often is the dog, as they are a farty bunch. In Ranger’s case we had additional evidence as on ultrasound I could see a lot of gas in his large intestine.

            “Good news! There’s more to come!” I cheerfully announced and pointed at the screen. Veterinarians and clinic staff are more or less immune to bad smells and so, apparently, was Ranger’s owner, so it was safe for me to be jovial about it. You do have to judge your audience carefully though.

            But why? Why are dogs such a farty bunch? There are two main reasons: gulping and fermenting. Let’s tackle fermenting first.

            Fermentation is the process by which microorganisms in an anaerobic environment (i.e. one with no oxygen) break down larger molecules into smaller molecules, often releasing gas molecules in the process. When bread rises or beer bubbles it’s because of the gas produced by the yeast fermenting the grains. In the case of Ranger’s large intestine, it’s bacteria fermenting food molecules that didn’t fully digest higher up in the small intestine. It’s impossible to know specifically which food molecules, but, much like in humans, peas, beans, dairy, complex carbohydrates and high fibre ingredients are at the top of the list. The list is really long though, so if the gas is a problem, the best first step is to switch to a new food that’s as different in its ingredients as possible. And when I say “problem”, I don’t just mean from a human olfactory comfort standpoint. I also mean from a canine abdominal comfort standpoint. I routinely have patients referred to me for abdominal ultrasound because of vague pain symptoms. Usually the referring doctor is trying to rule out a tumour, but often I end up finding excessive gas. Pardon me for asking a personal question, but have you ever had bad gas cramps? Gas is either embarrassing or funny or both until you have gas cramps, then you no longer care about the embarrassment and it sure is not funny anymore.

            The second major source of gas is gulping and this, in turn, happens for two different reasons. The first is that some dogs simply eat too fast and swallow a lot of air in the process. Correction – most dogs simply eat too fast. Humans are more likely to burp up swallowed air because of our vertical anatomy, but in dogs it tends to cruise on into the digestive system and pick up poopy odour molecules on its way to the rear exit. If you’re concerned about this you can try a so-called “slow feed” bowl, which typically will have a hump in the middle, forcing the dog to chase his food around the resulting doughnut. I have also heard of people scattering kibble across a cookie sheet to achieve a similar slow-down. The other reason for gulping is anatomy. Dogs with squishy faces such as boxers, pugs, Boston terriers, bulldogs etc. often have very narrow nasal passages, so they are forced to mouth breathe and consequently can swallow a lot of air.

            While fermenting and gulping account for most doggie flatulence, gas can occasionally also be related to disease in the digestive system, so please do mention it to your veterinarian, especially if there has been a sudden increase in the amount of gas.

            And what about cats? With the exception of cats who are given too much milk, farting is pretty unusual in this species. Their diets usually contain far fewer fermentable ingredients and although they can eat quite quickly, they do not generally gulp with the same wild “eating like nobody’s watching” abandon as the average food crazed dog.

            Before we leave this fascinating subject, I’ll give you a few nuggets of trivia for the next time conversation lags at a dinner party:

-          The scientific study of flatulence is called flatology. This is pronounced with a long a, as in slate or fate. So now you can add flatologist to the list of career ambitions for eight-year-old boys.

-          Dog farts objectively smell worse because of their higher protein diets. Protein digestion can produce sulfur containing amino acids that mix with the fermented gas to produce an especially fetid smell.

-          In 2001 the Waltham Centre for Pet Nutrition in England performed a study which involved fitting the subject dogs with special fart suits allowing them to collect the gas and analyze the sulfur content. I am 100% serious. Google “dog fart suit” if you don’t believe me. There are pictures too.

-          The average human produces 476 to 1491 ml of fumes per day, divided over 8 to 20… er… events. As the dog fart suit does not measure volumes, we sadly do not have this data for dogs, but, as I have outlined, they are a farty bunch, so even accounting for smaller size, we are talking about a lot of gas.

-          Although the exceptions are hilarious, most dog flatulence is silent. The reason for the difference with humans is anatomical. In deference to my more sensitive readers I will not expand on this. Yes, believe it or not, even I have my limits.

            Ranger’s ultrasound was ultimately normal. He had no tumours, or anything else of concern, and the amount of gas was not unexpected for an old lab. He was just slowing down, which was also not unexpected for an old lab.