Why the gallbladder is not present in horse?

The gallbladder is a small organ that stores bile, a fluid that helps digest fats. It is located on the underside of the liver and is connected to the small intestine by a duct. Most mammals have a gallbladder, but there are a few exceptions, including horses.

Horses do not have a gallbladder because their diet is high in fiber and low in fat. Fiber is a type of carbohydrate that is not digestible by humans or horses. As a result, it passes through the digestive system relatively quickly. Since fiber does not require a lot of bile to digest, horses do not need a gallbladder to store it.

In addition to their high-fiber diet, horses also have a large cecum, which is a pouch in the large intestine where bacteria ferment fiber. The bacteria in the cecum produce short-chain fatty acids, which are absorbed by the horse and used for energy. The production of short-chain fatty acids also helps to break down fiber, which further reduces the need for bile.

Without a gallbladder, horses must rely on their liver to produce bile. The liver produces bile continuously, and it is stored in the small intestine until it is needed. When food enters the small intestine, the bile is released into the digestive tract to help digest fats.

Since horses do not have a gallbladder, they can be more prone to certain health problems, such as biliary colic. Biliary colic is a condition in which the bile duct becomes blocked, preventing the bile from flowing into the small intestine. This can cause abdominal pain, vomiting, and diarrhea.

If a horse is experiencing biliary colic, it may be necessary to surgically remove the gallbladder. However, this is a relatively rare procedure and most horses can live healthy lives without a gallbladder.