Excerpt from Chapter 1 – Ground Rules for Feeding a Horse
Understanding the Digestive Tract of a Horse
The digestive tract of a horse is different from that of most other animals. Humans, cats, dogs, pigs, and other predators are able to digest meat and plant foods, but are not able to digest the fiber found in plants. This is because the digestive system does not produce the enzymes necessary to break down fiber molecules into small pieces. The result? The fiber leaves the body undigested as fecal waste.
But many animals have a four-compartment stomach that includes a “fermentation vat” where billions of beneficial bacteria live. These bacterial flora are quite capable of producing the enzymes needed to digest (break down into small pieces) the fiber found in plants. Ruminant herbivores, such as cows, sheep, deer, and goats, have this complex digestive system that is capable of efficiently digesting fibrous materials. They can take cellulose (one of the fibers found in hay, for example) and break it down into small molecules of simple sugar (known as glucose). In fact, if your goat gets hold of your cotton t-shirt, he can get glucose from it because cotton is the purest form of cellulose. Glucose is absorbed from the digestive system into the bloodstream, where it is transported to the animal’s cells to be metabolized for calories that keep the nervous system working, the heart beating, and the lungs breathing, as well as produce body heat and provide energy to do exercise.
I still haven’t told you about horses — that’s because horses are not like either one of these groups. They belong to a category known as “non-ruminant herbivores.” They are herbivores because they only eat plants. And they are non-ruminant because they do not have the four-chamber stomach that ruminants have. Instead, horses and all other equines, such as ponies, minis, donkeys, zebras, as well as the hippopotamus and the rhinoceros, have a digestive system that is a combination of ruminant and non-ruminant. They have a fermentation vat, called the cecum, that provides a home for fiber-digesting bacteria. But the cecum is toward the end of the digestive tract, and therefore not as efficient as the ruminant’s, whose fermentation vat (rumen) is toward the beginning. Therefore, horses need to consume much greater amounts of forages (hay and pasture) than cattle do to get the same number of calories.
HORSES NEED TO EAT HAY AND/OR PASTURE AT ALL TIMES
The most basic approach toward keeping your horse healthy is realizing that horses are “trickle feeders.” This means that they require a continuous supply of small amounts of forage. Horses in their natural setting will graze virtually all day, while taking approximately 2 hours each day to rest (though not at all one time). This is a very important concept to understand because a horse’s digestive system needs to have food in it most of the time, in order to avoid digestive problems. Horses’ stomachs, unlike our own, produce acid continually and if a horse consistently goes for more than 3 hours without anything to graze on, the excess acid can produce ulcers, as well as diarrhea, behavioral problems (because the horse is in pain), and even colic. Chewing produces saliva, which acts as a natural antacid, so if a horse has no hay or pasture, he will chew on anything he can to create saliva; some horses will start to eat their own manure. Furthermore, not eating is very stressful for horses, which results in the secretion of stress-related hormones. These hormones promote fat storage. So, putting an overweight horse on a “diet” by reducing hay consumption actually works in reverse — it promotes more weight gain. In addition, the reduced forage availability will make his metabolic rate slow down, causing calories to be burned at a slower rate. This, too, results in weight gain.
Horses are capable of self-regulating their intake when given the chance. If they are only offered a set amount of hay at a time, they will likely eat it very quickly and will be anxious for more. But if given all they want, they will overeat at first (for a week or less) and then, once they see that they can walk away and relax and the hay will still be there when they return, they will calm down and eat only what they need to maintain a healthy weight. If your horse is stalled at night, the only way to know whether he has enough hay for this self-regulation to take place is for some hay to be left over in the morning.
Pasture and/or hay offered free choice will affect how your horse behaves. The more you treat your horse like a horse in the wild, the calmer and more cooperative he will be. He needs to graze continuously, and he also needs to be able to interact with other horses. Negative behaviors such as cribbing, pawing, and irritability are often alleviated by feeding more hay and providing turnout with his buddies.