Excuse You: Is A Gassy Horse An Unhealthy One?

by | 02.15.2018 | 5:05pm

Budweiser's Super Bowl commercials are a hit every year. An amusing one from a few years ago showed a situation most horsemen have encountered — a horse with a bad case of the farts. (For those with delicate sensibilities, we're talking about flatulence, breaking wind, passing gas.)

As the late Dr. Doug Byars, longtime head of the medicine department at Hagyard Equine Medical Institute in Lexington, used to say, “A horse's digestive system was designed by a committee when God took the day off.” It's one of the more vulnerable systems horsemen must keep an eye on to assure it is functioning properly, or dire consequences could result.

When a horse begins to pass a lot of gas, horsemen become concerned. Is its digestion disrupted? Is this a precursor to colitis? Have bad bacteria overrun its gut? Will it get colic?

“Relax,” said Dr. Bill Bernard, former head of Rood & Riddle's internal medicine department. “If your grandfather farted, would you be concerned?”

Bernard explained that the horse's diet and the rate of motility in its intestines is responsible for flatulence.

“There could be a problem with the diet, or it could be a change in diet,” he said. “Some horses may have more gastrointestinal motility, faster motility, or there may be changes in motility, so the gas that would be let out gradually may be pushed out suddenly.”

In rare cases, gas can be a problem when a blockage in the gut causes distention, but most times it is just noisy, smelly, and sometimes embarrassing — especially when you are about to close a big deal with potential buyers standing next to the stunning animal.

“It all comes down to whether the horse is healthy,” Bernard said. “If he's passing a lot of gas and he's healthy, it's probably not a problem.”


The gut hosts an array of microbes that digest food to produce energy, vitamins, and other substances that benefit the body, while maintaining a balance between beneficial and harmful bacteria. This environment is called the flora or the microbiome, its new buzzword. When a horse's diet contains elements that enrich gas-producing bacteria in the microbiome, the horse becomes more flatulent—like a person who ate beans for lunch. Flatulence may suddenly develop, but after the gas-producing elements are digested and passed as manure, the horse should return to normal.

If the horse continues to pass gas to the displeasure of its owner, it's time to get the horse's diet back to basics.

“Try to go back to something bland—grass hay, oat hay,” Bernard said. “When we start feeding alfalfa and nice grains and a lot of fat and protein, that's not the normal diet of the horse. If you want to stop the flatulence, change to that bland diet. But you have to do it for awhile so the flora will adapt.”

Bernard has written several scientific papers on probiotics, and he recommends a particular species, Lactobacillus reuteri, to aid digestion and enhance the equine microbiome. L. reuteri is the beneficial bacteria most often identified in the stomach and colon of the horse. Some probiotic products may be derived from other species, such as the cow, so they are not as effective for the horse. L. reuteri has been shown to kill harmful bacteria in the gut, such as salmonella, without harming beneficial bacteria.

“What you want to look for in a good probiotic is one that has live bacteria and has large numbers of bacteria, billions of what are called colony forming units,” Bernard said. “And it needs to be species-specific, so you can't use cow L. reuteri in a horse.”

Bernard cautioned that if the increase in gas is combined with persistent diarrhea or  runny stools, consult a veterinarian to determine if there is an underlying problem. But he added that the rate of motility in the gut can fluctuate for a number of reasons that are not cause for concern.

“All this stuff isn't really that complicated,” he said. “If the stool is supposed to have water sucked out of it but it's moving through the colon too fast, then it's going to be watery.”

Are some breeds more gassy than others?

“I don't think it's related to breed as much as it's related to the diet that certain breeds would get,” Bernard said. “A Thoroughbred may get a different diet than a draft horse. Certain breeds may have more gas, but it's more likely not their genetics but rather their diet and flora.”

Bottom line: Just say “Excuse me.”

Twitter Twitter
Paulick Report on Instagram