Gas colic is the least serious form of colic. That’s the good news. The bad news is that it’s very common. So common, in fact, that it is often overlooked as “just gas,” like you might get when you eat too much pizza. However, never be complacent about gas colic because it can lead to complications such as displacement or twisting of the large colon.[i] Truth is, if you’re feeding correctly, gas colic should not happen. And if it does, then you’re more than likely doing something wrong.
The fibrous portion of plants doesn’t get digested until it reaches the hindgut (cecum and large colon) where it is broken down by the resident microbial population. This process, known as fermentation, produces volatile fatty acids (to be used for energy) as well as gas. Gas production is normal. In fact, a horse who has sufficient forage will often develop a “hay belly.” This is not fat, but rather, evidence of healthy gas production.
Horses produce tremendous amounts of gas, which is why they flatulate a lot! But, if the gas doesn’t adequately pass through the large colon, with all its twists and turns, it can build up. And there you have it – gas colic.
The exact reason for gas colic is difficult to assess, especially since most forms of colic involve some gas accumulation. But in general, gas colic can be caused by:
1) Limiting forage disrupts proper digestion. Horses require forage to be available 24 hours a day, all day and all night. Not that they actually eat during the entire 24 hours, but rather to simulate a natural environment where they can graze on forages as they wish. When they know that forage is always available, they slow down their eating, take time for a nap or socializing, and come back for more when they are ready. If this basic, foundational instinct is not met, the horse releases hormones which can create muscular spasms and interfere with the normal functioning of the digestive tract.
On top of that, hormones become out of balance, leading to inflammation of the hypothalamus, insulin resistance, and obesity. This is not the focus of this article, but I encourage you to read more about it.[ii]
When there is insufficient forage, the stomach accumulates acid, creating pain and mental discomfort. When the hay finally arrives, the horse will gorge himself, eating quickly and every bit in sight. He won’t chew as well, resulting in large amounts of undigested feed reaching the microbial population, resulting in excessive gas production.
Forage restriction also leads to ulcers anywhere along the gastrointestinal tract. Consequently, gas production increases because ulcers can interfere with digestion, allowing more undigested feed to reach the hindgut. Since ulcers can also bleed, blood flow to the large colon is diminished, inhibiting normal hindgut motility.
2) Confining your horse to a stall or small run/paddock reduces hindgut motility. When motility slows, gas cannot be expelled. The large colon is made of muscles which contract and relax in a peristaltic motion, moving digested material and waste products (including gas) along its length. When these muscles become “flabby,” movement becomes sluggish, leading to intestinal distress (colic). Gas accumulates, the intestine distends and pain-sensitive receptors in the large colon are stimulated, causing your horse to experience intense pain.
Blood circulation to the digestive tract is improved by moving around – simply grazing in the pasture, looking for the next tasty morsel, will add up of over the course of the day to more exercise than giving a horse an hour working in the arena. Standing for hours in a small space is very damaging to your horse’s digestive health.
There are literally thousands of studies showing the negative impact of stress on people’s health. Everything from irritable bowel syndrome, to heart disease, to autoimmune diseases, to obesity is impacted by constantly barraging our tissues with stress hormones, leading to a cascade of events that results in poor health. At the cellular level, the exact same thing is true for horses.
Stress exacerbates inflammation, which can damage any part of the body, but when the digestive tract is affected, the risk of colic goes up. Inflammation leads to ulcers, malabsorption, water imbalance, visceral fat accumulation surrounding the intestines, and microbial flora changes, all creating a scenario for colic.
Pasture turnout is the best way to reduce stress. Even a few hours each day will have a positive impact. If there isn’t pasture available, turn-out in an outdoor exercise area such as an arena (making sure there’s hay and water available) will reduce gas colic risk.
The hindgut microbial population must have time to adjust to any new food, so make sure give your horse’s digestive tract time to make the transition.
If you have to change hay every few weeks, an abrupt change of feed will put your horse at risk. Instead, do a little advanced planning and set aside a few bales of old hay, while slowly switching over to the new hay. You may find yourself regularly blending old and new hays since it is best to take approximately one week to make the adjustment. While doing this, offer your horse a prebiotic containing bacterial fermentation products to help adjust to a new forage source.[iii]
If you’re adding a commercially fortified feed to your horse’s diet to meet additional energy demands, make sure he already has some hay in his belly before feeding a concentrated meal. If you need to introduce a new product, take 2 to 3 weeks to safely change to a new feed.
Beware of weekly bran mashes. A bran mash, or any new feed for that matter, if unfamiliar to the hindgut microbial population, can trigger a dangerous colic attack. If you want to feed a warm bran mash, consistency is key – it must be fed every day, not once a week. Be sure to introduce it gradually and since bran is very high in phosphorus, choose a commercially fortified version that has added calcium.
In addition to a forage foundation, there are several supplements worth considering:
You are likely familiar with the movement to change your diet to “clean eating.” This simply means reducing the amount of “junk food” in your life and replacing it with whole, natural foods, clear of pesticides, preservatives, and inflammatory ingredients. In the horse world, there are two ingredients that we typically feed that are highly inflammatory: sugar and soy products. Most commercially fortified feeds contain both of these. Since these feeds often contain preservatives as well, fed over time, they can have a major impact on your horse’s overall health.
Slow feeder nets and containers are designed to simulate grazing.[vii] They must be kept full, or you’ll defeat your purpose. But when your horse knows that he will always have access to forage, he becomes calm and relaxed, rests more often, and walks away from the hay, knowing that it will still be there when he returns. In other words, slow feeders help your horse to “self-regulate” and eat only what he needs to maintain a healthy body condition.[viii]
Colic is rare among horses who graze on large pastures, simply because of their easy lifestyle and consumption of fresh, nutritious grasses. My goal in writing this article is to set a high standard, for all of us to strive toward. Still, I am vividly aware that many, if not most of you rely on boarding facilities and are not able to offer your horse acres of pasture. But once we know where we want to go, we are better able to get there.
Look into possible ways to increase outdoor grazing time. You may need to consider changing barns. Or perhaps your facility offers limited pasture turnout. Also consider using slow feeder systems in a stall at night so there is hay left over in the morning. In other words, the most significant change you should strive toward is how to make hay available 24 hours a day.[ix]
Every little improvement makes a difference, for your horse and for other horse owners boarding at the same location. You might just become a trailblazer!
Take control of your horse’s environment and feeding, by focusing on Nature’s rules to avoid gas colic. Remember, your horse is a grazing animal, requiring a steady flow of forage at all times. Feed him, simply, like a horse!
[i] For more detailed information about colic, its forms, prevention, and what to do, please read the section on colic in Chapter 14 – Digestive Problems, of Feed Your Horse Like A Horse
[iii] Ration Plus is an excellent prebiotic to use when changing forage (and other feed) sources.
[iv] BPlex offers all 8 B vitamins, without added iron.
[v] Yeast Plus offers both live Saccharomyces cerevisiae and yeast culture.
[vi] Colostrum from Forefront equine is of high quality.
[vii] Getty, J.M. 2014. The correct way to use slow feeders.
[viii] Dr. Getty recommends several Slow Feeders, available at Dr. Getty’s Free Shipping Supplement Store.
[ix] Many horse owners fear weight gain with free-choice forage. Ironically, restricting forage keeps horses overweight. Read articles on "Overweight Horses" in Library Resources.
For permission to reprint this article, in part or in its entirety, please contact Dr. Juliet Getty directly at Gettyequinenutrition@gmail.com.