Understanding the anatomy of the digestive system is a key component in managing a healthy horse.
Here's just one example: There is no mammal that can synthesise the enzyme cellulase which breaks down the complex insoluble carbohydrate, cellulose, found in grass. This is why when we can get no nutritional value from eating grass. Some grass eating mammals have evolved ways to overcome this problem. The horse has developed a particularly large hind gut (represented by the copper and reddy-brown in the painting) to house billions of these micro-organisms and friendly bacteria. In return for a warm environment and ready supply of food the micro-organisms break down the cellulose into a digestible form, the by product of which is heat.
The micro-organisms are highly sensitive to change. They are likely to die off if there is a sudden change in diet, if the horse eats too much starch, stress levels rise, if the horse does not eat for long periods or if there is a change in pH within the gut. This often results in scouring and poor gut health. To learn more about applying digestive anatomy to horse care and management you will enjoy 'Horse Anatomy for Performance'.
Also check out the digestive seminar Digetsive Anatomy, Feeding and Nutrition.