Flatulence in Dogs

My dog has excessive gas. What is this called?

The excessive formation of gas in the stomach or intestine is referred to as flatulence. Flatus is the medical term used to describe air or gas expelled through the anus.

What causes flatulence in dogs?

The most common cause of flatulence is a change in diet or eating something spoiled (dietary indiscretion). Most cases of chronic flatulence are caused by a diet that is poorly digested by the dog. 

A poorly digested diet causes excessive fermentation in the colon and subsequent gas formation. Soybeans, peas, beans, milk products, high-fat diets, and spicy foods are all commonly associated with flatulence in dogs.

Most dogs and cats are lactose intolerant and experience flatulence and/or intestinal upset if they are fed milk or dairy products. A dog that is fed a premium diet and still experiencing flatulence should be tested for a problem with either poor digestion or poor absorption of nutrients from the diet. Anything that causes a change in the microbiome (gut bacterial population) can lead to flatulence.

Dogs that swallow air while eating, especially those that eat rapidly, are more likely to experience flatulence. Brachycephalic dogs (dogs bred for short noses such as bulldogs and pugs) swallow more air in general due to their breathing difficulties. Overweight, obese, and sedentary dogs are at higher risk for developing chronic flatulence, regardless of diet.

What are the clinical signs of flatulence?

The most common clinical signs include expulsion of gas from the anus, with or without odor; mild abdominal discomfort; mild stomach distention or bloating; and excessive gaseous sounds or rumbling from the abdomen (borborygmus). If the dog has an underlying gastrointestinal problem that causes an inability or impaired ability to absorb nutrients for the body, clinical signs will also include loose stools or diarrhea, vomiting, and weight loss.

How is the cause of flatulence diagnosed?

Diagnosis is based on medical history and clinical signs. Some of the common causes that must be ruled out include:

• Increased swallowing of air (aerophagia)
• Gluttony or compulsive eating
• Respiratory disease
• Feeding shortly after exercise
• Brachycephalic or flat-faced breeds
• Dietary indiscretion
• Diets high in soybeans, peas or beans
• Diets high in fermentable fibers such as lactulose, psyllium, or oat bran
• Spoiled food
• Milk and dairy products
• Sudden change in diet
• Spicy foods and food additives
• Inflammatory bowel disease (IBD)
• Small intestinal bacterial overgrowth (SIBO)
• Tumors
• Irritable bowel syndrome (IBS)
• Intestinal parasites
• Enteritis
• Exocrine pancreatic insufficiency (EPI)

Diagnostic tests may include fecal examination and/or culture; rectal cytology; blood and urine tests, including specialized tests such as trypsin-like immunoreactivity (TLI), serum cobalamin, and serum folate tests; abdominal X-rays; abdominal ultrasound; and intestinal biopsies.

How is flatulence treated?

Treatment is based on diagnosis and commonly involves a change in diet. Recommendations include a diet that is highly digestible, with low fiber and fat, which reduces the amount of food that needs to be digested and absorbed before reaching the pet’s colon.

"Treatment is based on diagnosis and commonly involves a change in diet."

Medical therapy may include probiotics (beneficial bacteria that aid digestion) along with prebiotics (food for the beneficial bacteria) to promote a healthy microbiome. 

Small, frequent feedings are encouraged for dogs that eat rapidly or are hyperexcitable. Your veterinarian will outline a treatment plan specifically designed for your pet.

What is the prognosis for resolving flatulence?

Most patients with uncomplicated cases respond well to dietary and lifestyle changes. Once offending dietary substances and products are identified, it is important to avoid them.