Ruminant Digestive System Ms. Zubiate What is a ruminant animal ? A grazing animal that has a digestives system with 1 stomach containing 4 parts. 1. Other characteristics: No upper incisors (teeth) called a dental pad. 2. Chews cud (soft mass of already chewed food) that is brought back up through the esophagus. 3. All ruminants are herbivores, meaning they only eat plant matter. Can you think of any ruminant animals? Pathway of food through digestive system. 1. mouth 2. esophagus 3. rumen 4. back to mouth for “chewing of cud” 5. Reticulum 6. omasum 7. abomasum 8. small intestine 9. Large intestine Getting Started! 1. Using prehensile organs (lips & tongue) the animal take food into its mouth where it is then broken down using the teeth. The esophagus 2. After the food is broken down into smaller particles it is swallowed and passes through the esophagus using muscle contractions known as peristalsis. Muscle contraction is called peristalsis: The rumen 3. The largest compartment of the ruminant stomach is the rumen. This is where the food that the animal has been taken in is mostly fermented, it also houses the bacteria, protozoa, and fungi that aids in the breaking down of food. Microbes in the rumen are what break up the plant matter and convert it to energy that the animal can use. Fermentation also produces large amounts of gas. RUMEN Chewing cud Food that is stored in the rumen is regurgitated back up through esophagus to be re-chewed in the mouth. This is know as “chewing cud”. Food can be rechewed more than one time. The food that is regurgitated back into the mouth is known as a bolus. Once the food has been broken down enough it will then move onto the next step in the digestion process of being swallowed, moved through the esophagus then back into the rumen. The reticulum 4. Once food is broken down small enough it will travel from the rumen to the reticulum. The reticulum is the honeycomb shaped on the inside and is very tough. The reticulum can trap foreign objects that should not have been eaten in the first place, such as hardware. RETICULUM The Omasum 5. Food enters the omasum after leaving the reticulum. The omasum acts as a filter to absorb water and nutrients from what has not been digested yet. The omasum resembles an open book because of its “pages” texture. Omasum Abomasum 6. Once leaving the omasum the rest of the plant matter will enter the abomasum. The abomasum is also known as the true stomach. In the abomasum gastric juices, hydrochloric acid, and digestive enzymes break plant matter down into its most basic molecular components so that the walls of the intestines can absorb them. Abomasum Small intestine From the abomasum the plant matter will then travel to the small intestine. Here, it is exposed to enzymes from the pancreas and intestinal walls, and bile from the liver. Dietary protein, starch, sugars, and fats are all completely digested here to enter the bloodstream. Small intestine large intestine Following the small intestine any remaining plant matter will pass into the large intestine. This is the second site of fermentation (after the rumen) where excess water is reabsorbed. The large intestine is the final site of the large intestine gastrointestinal tract (GIT), and will hold feces until it is expelled through the anus.