For the new horse owner, it’s simple. Feed a few scoops of grain with some hay in the stall twice a day and you’re set, right? I mean…it’s a horse. Surely they work the same way as other pets, like dogs and cats, right?
I mean, seriously wrong. Thinking of your horse as just another pet, or using a human feeding schedule can actually cause serious problems. To understand why, we need to understand the difference between horse digestive systems and humans or other animals.
Horses are bigastric animals. They have two sections in their digestive system that perform different functions in order to extract nutrients from food. Humans, dogs, cats, etc. have a monogastric system – one section does it all. Failure to understand this crucial difference is where problems can develop.
Image courtesy of SmartPak.
The horse digestive system is divided into the foregut and hindgut. The foregut contains the stomach and small intestine. This is where initial digestion takes place. In the hindgut, consisting of the cecum and colon, or large intestine, final digestion occurs, with sugars and starches being extracted before the non digestible portions exit the body.
When a horse chews food, whether grain or hay, it is chewed and rolled into what’s called a “bolus” – a blob of food. One interesting fact is that each “bite” of food is chewed on alternate sides of the mouth…first bite on one side, next bite on other side, next on first side again, then the opposite, etc. This is mixed with saliva and swallowed, where it travels to the stomach.
The horse stomach is the smallest in size relative to other domestic animals. It can only hold 2-3 gallons. Food remains in the stomach for as little as 20 minutes for liquids and wet grains, to up to 12 hours for hay and forage. The upper 1/3 of the stomach is “non-glandular”, meaning it does not produce gastric acid, and is unprotected from those acids. This is an important point to remember, as 80% of ulcers develop in this area.
The small intestine comes next, being 70 feet in length. It can take up to 8 hours for food to move through this area.
In the second section of the equine digestive system, the first stop for the food is the cecum. It’s a fermentation vat that holds 8 gallons. Interestingly, the process of fermentation in this part of the horse provides an enormous amount of internal heat that keeps the horse warm in colder weather. That’s another reason to be aware of your feeding schedule, as it functions as an internal space heater.
After the cecum is the large and small colon, with a combined length of around 20-25 feet. Final digestion takes place here, with bacteria breaking down complex carbohydrates. Another thing to remember is that the “bacteria load” adapts to the predominate food source. What this means is that changing feed rapidly can cause digestion issues, as the bacteria need from a few days to up to a week to adapt to a new food. Always blend in new feed with the old over a weeks time at least to forestall problems.
Total time for digestion from mouth to anus can range from about one day to as long as five days, depending on what is being eaten, with forage and hay taking longer than grains.
Ok, so now we have a working knowledge of how the horse digestive system operates, let’s look at potential problems. The first and probably most important one concerns the stomach.
Horses produce up to 16 gallons of gastric acid every day. Yup, 16 gallons. The size of a mid sized car’s gas tank. And they produce it continuously.
Your stomach only produces acid when it gets the “signal” from chewing that “food is on the way”. Horses are different and are always producing acid. This isn’t a problem with wild horses, or pasture boarded. But when we get to stalled horses, it becomes a major issue. Many times, a horse is fed two, maybe three meals a day…like you and me. Problem is, once the food leaves the stomach, if there is a long period between feedings, all that stomach acid starts working on the stomach lining. Remember the upper third of the stomach that’s unprotected? That’s right…ulcers.
“But what about grain? I feed my horse lots of grain. That’s good, right?” Well…yes and no. Horses evolved to graze for 18-20 hours per day, keeping a steady supply of forage entering the stomach. The entire digestive system is made to break down roughage. Most grains are nothing more than starch and sugars. If too much is fed, and some sources cite anything over 5 pounds per feeding, a lot of it is passed into the hindgut undigested. This can interfere with the natural digestion process, leading to colonic acidosis, colic, etc. If you have a hard working horse or hard keeper, then the extra sugars from the grain can be a good thing, as long as it’s in moderation with free choice grass or hay at all times.
But we are getting off the subject. The point of this post is to point out that horses are continuous feeders. They simply are not designed to eat one or two meals separated by hours of an empty stomach. Whether it’s a hay rack in the stall, feedings every three to four hours, or lots of grazing time, horses need a nearly continuous intake of roughage 24/7 in order to stay healthy and happy. If you are boarding remotely, after the morning meal they should be turned out for the day for grazing time. At night, make sure you provide enough hay to last until morning.
This is the schedule we use for our rescue horses and it works well. They are healthier, happier, and have far fewer health issues. There’s an adage that says most illnesses can be traced to nutrition. There is more truth in that statement than most people realize.