by By Ken Wilkinson, Nutritionist

Many are familiar with the fact horses ferment fiber in the hind gut via the microbial population back there and derive most of their energy from that (at least at maintenance levels of activity).  If more energy is needed, we add higher energy, lower fiber feeds to the diet which are digested more up front.

 I would like to move even further back and start a discussion about how horses actually eat. This is the nutritional strategy of the horse. It begins with looking at the mouth.  A horse can select a higher quality diet than a cow for example because of its prehensile lips and the incisor teeth allow him to clip grass off close to the ground.  He can literally eat the highly nutritious crown portion of the grass plant.

 Cows on the other hand tend to eat forage by sweeping up  a large volume with their tongues, which are rougher and they consume a high amount then go and lay down and ruminate to digest the food. Predators are taken care of by wild cattle who have horns and can stand and fight in a defensive circle. Horses must fight or run.. Cows do not even have top incisors.

  Horses have a relatively small stomach at 8-12 liters; compared to a cow with a 200 liter rumen. Horses are designed to eat a lot of small meals throughout the day, move the food down the digestive tract and ferment it as well as possible in the hind gut which is smaller than a cow’s rumen. They tend to be able to select a decent diet in adequate amounts, if plenty of range forage is present, but this may require 10-12 hours of actual eating time and 15-16 hours of grazing time while moving over the range eating many small meals.

 Because the hind gut full of forage and water is in the back it is actually an advantage for the horse when he runs because the weight of this material moving back and forth in the body cavity pushes forward on the diaphragm helping him breathe out and as it slides back, when he rocks back in setting up the canter it pulls back and allows the horse to inhale. The piston action therefore helps him run so that his stride rate matches his breathing rate up to about 100-120 breaths per minute They may breathe on every second stride as well.

 A major feature about how horses eat compared to us or other animals, is that horses do not produce saliva at the sight and smell of food.  This means horses must have the tactile feel of food on the palate to stimulate saliva production.  This is critical as the saliva carries a mucous to lubricate the food bolus and it carries sodium bicarbonate to buffer the acid in the stomach. This is a first line of defense against choke and colic.  Horses need to have a chewing factor from forage in their diet.

 You can appreciate that a horse fed hay intermittently and without adequate supply of water is in a difficult situation. If your horse objects to a wormer tube being thrust into his dry palate, maybe you are the problem and he is not being bad in rejecting that.

 So digestion begins right up front in the mouth. Good tooth care is critical, and  you must carefully monitor your horse’s mouth cavity to make sure sticks and things are not stuck in the palate. The feeding of horses begins with providing hay of good quality that will stimulate chewing but that is not so coarse that a horse cannot chew it at all. Feed enough to mimic nature, usually a minimum of 1.5% of body weight and try for 2.0% if possible. This is 15-20 lbs for a 1000 lb. horse.

 Try not to leave your horse for long periods without hay, such as over 5-6 hours during the day. Out on range horses get up in the middle of the night and graze a bit, so feeding little and often is ideal. Make sure water is adequate since 1 lb. of hay will require about 5 lbs of water.

In the next article we will discuss the unique aspects of the horse’s stomach and how we need to consider feeding to keep the horse healthy and happy.