Mouth • I am the mouth. I produce saliva which loosens and softens the feed and eases passage to the stomach. My saliva contains bicarbonate which buffers the acid found in the stomach. The more forage I chew, the more saliva I produce.
Esophagus • I am the esophagus. I am a long muscular tube connecting to my neighbors the mouth and the stomach. I sometimes suffer from “choke” if the mouth has poor dental health.
Stomach • I am the stomach. My most important job is to churn up and liquefy the feed that comes in. The gastric acid that I contain helps break down the particles of feed and the enzyme “pepsin” starts the digestion process for the protein within the feed. Because I produce so much acid, I need regular amounts of forage throughout the day or I may suffer from ulcers.
Small Intestine • I am the small intestine. I am where most of the digestion and absorption occur for the sugar, starch, protein, and fat. I also soak up Vitamins A, D, E, and K along with Calcium and Phosphorous. My buddy the pancreas shoots me some enzymes to finish breaking down the protein into single amino acids. These amino acids are quickly soaked up into my bloodstream to be used for building new cells.
Cecum • I am the cecum. I am the first stop in the Large Intestine. I can hold up the 15 gallons of fluid and digested feed. I contain billions of bacteria and protozoa who do all the work for me. These guys produce enzymes that can break down the tough fiber of the forage that comes in. This may take anywhere from 36 to 48 hours. From this process I make volatile fatty acids (VFA’s), heat, water, and gas. The VFA’s are a great source of energy and are soaked up into the bloodstream. The bacteria who work for me also produce lots of Vitamin K which is also quickly soaked up.
Large Intestine • I am the Large Intestine. I contain the cecum and the colon. My most important job is to absorb water. My neighbor, the small intestine, secretes about 30 gallons a day and I have to soak most of it back up or it will be lost. I also create fecal balls (after soaking the water out of the digested feed).
Rectum • I am the rectum. My job is to contract muscles to evacuate the fecal balls through the anus. These are then deposited on your stall floor. I am the final stop through the horse’s GI tract.