Today I had the opportunity to meet with a renowned equine dentist who does so much more. She imparted an overwhelming amount of knowledge on me, and I want to share what I learned.
She arrived and immediately assessed my rescue gelding. She explained that he was a little thin and had a behavior issue (we were fully aware of this- in fact we have tried a Panacea power pack, over feeding, chiropractics, and cold laser therapy to address these issues, in addition to a visit from the vet).
She took a look in his mouth and explained that his canines were covered in a tartar ball. This can lead to severe decay and even tooth loss. She went on to explain how the horse chews and digests in a very different way than what I had considered. She explained that a horse eats a piece of hay, and it gets cut up six times based on how the horse articulates its jaw as it chews in a circular motion (causing hooks). They basically finely chop the hay, the more they chew it. Also, the horse uses a different grinding stroke when eating oats. The chewing pattern changes with each type of food. The food is mixed with saliva which contains two ingredients, that help to launch the digestive process. The first is bicarbonate, which buffers and protects against amino acids in the stomach. It also contains small amounts of the enzyme amylase, which assists with carbohydrate digestion. Once the food is ground up into smaller particles by the molars, it is swallowed and travels down the esophagus which is 50 to 60 inches in length, to the stomach.
The horses stomach is very small compared to the size of the animal and makes up only about 10% of the digestive system. It can vary in size from about 8 to 16 quarts, and functions best when it is about 3/4 full. Food passes through the stomach relatively quickly, about 15 minutes, where it is mixed with pepsin, an enzyme used to digest protein and hydrochloric acid to help break down particles. Very little fermentation should happen in the stomach, as this will cause gas, and result in color. One the food passes through the sacks caucus, tunic region and pyloric, it moves to the small intestine, at this point, fermentation has ceased and protein digestion increases. It is in the small intestine where serious digestive processes take place. The intestine secretes enzymes in addition to the enzymes secreted by the pancreas to break down proteins into amino acids. Some of this is absorbed into the bloodstream and the rest moves to the large intestine which has 5 basic parts. The key part being the cecum (see-kum) which is about four feet long and one foot in diameter. The cecum can hold 8-10 gallons of food and water, and this this is where undigested food from the small intestine, such as hay and grass, is broken down and fermented. The food enters and exits the cecum on the same manner, think of a fermentation vat. If the horses id dehydrated, impaction can occur at the lower end of the cecum, causing colic. Food remains in the cecum for up to 7 hours allowing the bacteria and microbes to do their jobs, resulting in vitamins and fatty acids which are absorbed into the cecum.
"The microbial populations within the cecum become specific for digestion of the type of food that the horse normally ingests. It's very important to change a horse's diet gradually in order to give the microbes an opportunity to adjust, which could take several weeks."
The remnants from the cecum travel to the large colon, where microbial digestion continues, and a lots of the nutrients, mostly b-vitamins, minerals and phosphorus, are absorbed. This is where a twisted gut occurs as well. The late colon has a right and left ventral colons and a dorsal colon. The ventral colons consist of a series of pouches, which can become twisted and fill with gas during the fermentation process. Next the food moves to the small colon, at this point all, nearly all of the nutrients have been digested, and the remnants will be stripped of moisture which is absorbed back into the body. During that process, fecal balls are formed which are passed through the rectum and out of the anus. So there you have it, start to finish, and why teeth affect the entire digestive systemm of a horse.