What Do Horses Eat? Are They Herbivores or Omnivores?

Horses are Herbivores

Horses have evolved as grazing animals, strictly consuming a plant-based diet. They have adapted to a low-energy, high fiber diet. Horses are designed to constantly eat unless resting, moving, or socializing.

There are stories of horses consuming meat as a means of survival, but they are not omnivores by choice. Horse’s will eat something new that they are exposed to; although, that doesn’t mean that they should. Their digestive tract is designed to digest grass, hay, and other plant-based foods.

The Digestive System of Horses

The horse’s digestive system can be divided physiologically into two main groups: the foregut and the hindgut. The foregut consists of the mouth, esophagus, the stomach, and small intestine. The purpose of the foregut is to digest the non-fibrous nutrients in the horse’s diet. The hind-gut is essentially made up of the highly developed large intestine which consists of the cecum, the large and small colon, and the rectum. The hind-gut is evolutionarily optimized for the fibrous portion of the equine diet. Grass and hay consumed undergo fermentation in this portion of the digestive tract.

As a grazing animal, the digestive tract of the horse is intended to process small amounts of food several times throughout the day. This is what the typical diet looks like for wild horses. Domestic horses, on the other hand, are restricted to two meals per day, morning and evening.

Horses’ Teeth

Horse’s have a very unique mouth; with their teeth divided into two major sections: the incisors at the front of the mouth and cheek teeth located toward the back of the mouth. The purpose of the sharp incisors teeth are for grabbing and tearing, whereas, the cheek teeth are the flat grinding teeth.

Canine and wolf teeth for horses are located between the incisors and the premolars. All male horses and a small percentage of females grow canine teeth. Both males and females grow wolf teeth. Located more towards the front of the mouth, near the incisor teeth, are the canine teeth which are used as a defense mechanism to fight off predators and do not assist with chewing. Wolf teeth are a vestigial structure within the mouth, meaning that at one point they were functional but evolutionarily lost their function.

The purpose of teeth in the equine digestive system is mastication, the manual chewing and breaking down of food and plant matter. Digestion begins in the mouth. Saliva contains enzymes that start to break down food materials during mastication.

Balanced Diet of a Horse

First and foremost, horses should always have constant access to clean water. Aside from fresh water, a horse’s dietary needs consist of 5 major nutrients in their diet: proteins, carbohydrates, fats, vitamins, and minerals. A good quality horse feed will incorporate each of these to ensure a well balanced equine diet in every single serving. But horse feed should not be the only source of food. Horses are grazing herbivores. They require fibrous materials. Good examples being grass and hay. Hay is forage grasses that have been harvested, dried and baled together primarily in small square bales or large round bales.

Protein is made up of amino acids, which are required for muscle growth and recovery. Sources of protein in the equine diet include soybean meal and alfalfa. Carbohydrates is a horse’s main source of energy and calorie intake. Soluble carbohydrates (corn, barley, oats) are digested in the foregut, while the insoluble carbohydrates (fiber) are fermented by microbes in the hind-gut.

Fats are required but it small quantities as they take a longer time to digest. Fats helps the body absorb fat-soluble vitamins (A, D, and E) meaning these vitamins can only be absorbed by the body in the presence of fats. Most vitamins are found in green, leafy forages, except Vitamin D which is obtained by exposure to sunlight. Horses stalled during the day time with limited access to sunlight should be supplemented Vitamin D. Otherwise, a horse with regular access to fresh grass or good quality horse feed will have an adequate amount of vitamins in their daily diet.

Minerals are essential for maintaining body structure, fluid balance, nerve conduction, and muscle contraction. Only smaller doses of macro-minerals (i.e. calcium, phosphorus, sodium, potassium, chloride, magnesium, and sulfur) are needed daily. But, again, if a horse is consuming fresh grass or good quality horse feed, they should already be receiving the proper amounts of minerals in their diet, except for sodium chloride (salt) which should always be available in the form of a salt block.

Feeding Based on Size of Horse

Ideally, a horse should eat at a rate that is 1.5-2% of the horse’s body weight. A horse that is 1,200 lbs should consume about 20 lbs per day. Forage should always be the base of the equine diet. Always feed the most forage possible and then supplement additionally with high quality horse feed.

Horse stomachs are small so any supplemented form of concentrates (i.e. horse grain) should be fed twice a day, if not more. A horse should not be fed more than 0.5% of their body weight in concentrates per feeding. Horses with higher dietary needs, such as a lactating broodmares or exercising performance horses, should be supplemented accordingly with grain.

Ruminant vs Non-Ruminant Animals

Horses are non-ruminant herbivores also known as hind-gut fermentors. A non-ruminant or mono-gastric animal is an animal with only one stomach. They have an entirely different gastrointestinal tract than cattle which are ruminant herbivores. Ruminant animals have four-chambered stomachs, made up by the rumen, the reticulum, the omasum, and the abomasum. The four chambers of the ruminant gut allow for full digestion of grass and other plant material without completely chewing it. They are only required to partially chew their food and the microorganisms in the rumen break down the rest.

A quick way to determine if an animal is ruminant or non-ruminant is by looking at the feet. Often you will find ruminant animals to have two-toed hooves such as cattle, deer, sheep, and goats. Non-ruminant animals typically only have a single, non-split hoof.

Another characteristic of ruminant animal is the chewing of cud. Herbivorous grazing animals are prey animals. They evolved to quickly gather their food, store it in a sack within the abdomen and later regurgitate the stored food, referred to as cud to further chew on and fully begin the digestion process. Mono-gastric animals do not chew cud and rarely even have the ability to vomit.

Why Can’t Horses Eat Cattle Feed?

The digestive system of a horse and a cow are so majorly different that even a small amount of food can cause a serious health issue. Most cattle feed contains additives that are toxic to horses, such as ionophores. Ionophores are a class of antibiotics used specifically in cattle to increase feed efficiency by altering the fermentation process.

What Food is Toxic to Horses?

The horse’s digestive tract can be very sensitive. They can eat a variety of foods but there are eight foods that they should never consume:

1. Chocolate
2. Persimmons
3. Avocado
4. Lawn Clippings
5. Fruit with pips and stones
6. Bread
7. Potatoes and other night shades
8. Yogurt and other dairy products

Lawn clippings may come as a surprise as it is essentially grass. However, regularly mown lawns contain dangerously high levels of fermentable carbohydrates. Excessive intake of lawn clippings can lead to a high rate of fermentation in the hind-gut, disrupting the horse’s gut microbial balance and potentially resulting in founder or colic.

What Food Can You Give a Horse as a Treat?

Carrots and apples are traditional favorite treats. Purchased pre-made horse treats, sugar cubes, sunflower seeds, raisins, peppermints are all great treats for a horse in limited quantity.

What is Foundering?

Foundering is a metabolic disorder also commonly referred to as laminitis. It occurs when the horse’s hoof becomes so swollen from inflammation, it becomes painful for the horse to put weight on it.

There is five main reasons a horse can founder:

1. Overeating
2. Working on a hard surface (road founder)
3. Running high fever
4. Exposure to black walnut shavings
5. Stress

Long term over-consumption of grain feed or singular grain engorgement can induce founder. A diet too high in sugar and starch can result in reduced blood flow to the feet, inducing inflammation. Horses’ diets require forage. They truly only need grass and hay to be healthy. Grain is often incorporated when they cannot graze all day on grass or are being exercised and their energy needs need to be supplemented with concentrate in the form of a horse grain.

Founder is a serious condition that can result in permanent lameness. If caught and treated early, horses can recover from founder. However, if left untreated and allowed to progress, founder can result in death.

What is Colic?

Colic in horses is defined as abdominal pain; however, it is often used to refer problems with the gastrointestinal tract. Common causes of colic include:

• high grain/low forage diets
• moldy feed
• abrupt diet changes
• parasitic infection
• sand consumption
• stress
• lack of water

Colic is, for the most part, preventable. Horses should eat on a consist schedule, especially if their diet is strictly controlled and they have limited access to forage throughout the day. Sudden changes in their diet should be avoided. Clean, fresh water should be available at all times. A lack of water can lead to a blockage of food material within the digestive system, leading to an impaction colic.