WHITETAIL DIGESTION SYSTEM
Digestive System: Members of the deer family, unlike most mammals, do not have any teeth in the front of the upper jawbone. Replacing the teeth is a resilient pad that makes contact with the lower incisors. Deer have 32 teeth: 8 incisors, 12 premolars, and 12 molars. They usually do not have any canine teeth. The members of the deer family are ruminants, having a four-compartmented stomach, which allows the deer to feed very rapidly, chewing its food just enough to swallow it. This partially chewed food goes into the storage section of the stomach known as the rumen.
A feeding deer is at a disadvantage because while feeding it cannot be alert to danger. Not having to masticate its food thoroughly, the deer can fill its paunch rapidly and then retire to a safe place to do the job properly. When the deer is ready, it regurgitates a ball of partially chewed food about the size of an orange and rechews it. It then reswallows the food, which now enters the second section of the stomach, the reticulum. From there, it goes into the omasurn, then through the abomasum into the intestines where digestion is completed. Deer do not have a gall bladder on their livers. This allows them to eat vegetation that would kill domestic animals.
Deer are ruminants, meaning they are equipped with a four-chambered stomach. An interesting characteristic about the ruminant’s stomach is that it allows the animal to gather a lot of food at once, then chew, and digest it later. The four chambered stomach is needed to process the large quantities of low nutrient food the deer eat. Depending on the type and abundance of food, the deer can fill its stomach in about one or two hours. When a deer eats, food is moved by the tongue to the back of the mouth, where it is chewed just enough to swallow. The food then passes down the gullet into the stomach. The four sections of a deer’s stomach are the rumen, the reticulum, the omasum, and the abomasum. First, the food goes into the rumen which stores 8 to 9 quarts of unchewed food and acts as a fermentation vat. Most of the digestion occurs in this area of the stomach.
Deer depend on billions of microorganisms that live in its stomach. These microorganisms break down the fibers, cellulose, and other basic plant components, and convert them into materials that can be used by the deer’s digestive system. The lining of the rumen has small spaghetti-like fringes called papillae, which vary in length from 3/8 to 1/2 inch. Over 40 percent of a deer’s energy is derived from the acids absorbed through the papillae and the walls of the rumen.
After the deer has filled its paunch, it lies down in a secluded place to chew its cud. After chewing its cud for awhile, the deer re-swallows the food, which then passes to the second portion of the stomach, the reticulum. The reticulum has a lining that looks like a honeycomb. The reticulum holds the food in a clump, which can grow to the size of a softball. The main function of the reticulum is to filter out any foreign material.
After about sixteen hours, the food passes to the third chamber, the omasum, where intensive digestion and absorption take place. The omasum’s lining has forty flaps of varying heights, which absorb most of the water from the food. The last compartment, the abomasum, has a very smooth, slippery lining with about a dozen elongated folds. The abomasum produces acid to break down the food pieces for easier absorption of nutrients. The food eventually passes through 67 feet of intestines, where most of the liquid is absorbed, leaving an impacted mass of undigested particles. These particles are passed out as excrement.
A deer goes to the bathroom an average of 13 times every 24 hours. Usually 65 percent of the food will be used by the animal, and 5 percent is lost as methane gas, 5 percent as urine, and 25 percent as feces.