Ruminant Digestive System

  • What is a ruminant?
    • Ruminants are animals that have one stomach with four compartments. The compartments are as follows:
    • Rumen
    • Reticulum
    • Omasum
    • Abomasum

 

  • Four Compartments

    • Rumen
    • Largest compartment
    • Storage and fermentation
    • Located on left side of the cow
    • Reticulum
    • Resembles honeycomb
    • Separated only slightly from the rumen
    • Heavier objects are caught in this area
    • Source of “hardware disease”
    • Omasum
    • Often called “many-piles,” since it is layers of tissue that resemble pages in a book
    • Water/liquid absorption
    • Abomasum
    • Referred to as the “true stomach”; similar to the stomach in a monogastic
    • Has hydrochloric acid and a glandular lining
    • Digestive enzymes are introduced here

  • Digestive Pathway https://www.youtube.com/watch?v=SVNNJf_28KE

    • Food is ingested through the mouth. Cows are unique. They possess a dental pad instead of top teeth. The food is grasped by the tongue and ripped off. Food is broken into smaller pieces, mixes with saliva and is swallowed

    • Food moves down the pharynx or throat and through the esophagus

    • Esophagus, a long narrow tube connecting the throat to the stomach. Peristalsis (wavelike contraction) helps propel the food.

    • Food then moves into the rumen, the holding vat. Beneficial bacteria break down and digest the food, and papillae, “finger-like projections,” absorb nutrients that are created from the bacteria

    • Rumen Papillae

    • Cows lack digestive enzymes to digest plant material directly due to their inability to break down cellulose

    • The rumen possesses billions of beneficial bacteria that digest feed the cow had eaten

      • The feed is fermented, and volatile fatty acids, proteins and B vitamins are produced
      • The rumen in a cow can hold up to 50 gallons of digested feed

    • The reticulum is only slightly separated from the rumen. Food passes back and forth The Reticulum

    • Filtering occurs, keeping particles inside the rumen

    • Food is then passed back up to the esophagus and throat as a bolus, a small mass of food. This is referred to as “cud”

    • Saliva, a critical component of cud chewing, buffers the rumen. This is similar to taking an antacid

    • Cows produce up to 50 quarts of saliva daily

    • Food repasses into the reticulum and backflows between the reticulum and the rumen for further digestion. Then it passes into the omasum

    • The “cud” passes into the omasum The Omasum

    • Primary purpose is water absorption and absorption of substances from digestion

    • This organ is lacking in modified ruminants/pseudoruminants

    • The abomasum functions similarly to the mongastric stomach Abomasum

    • Acids, buffers, and enzymes break down food

    • Food continues on into the small intestine where nutrient absorption and water absorption occur

    • Enzymes are secreted in the from the pancreas and liver

    • Three portions in the small intestine: duodenum, jejunum, ileum

    • Food continues on into the cecum, the first part of the large intestine. Food continues through the large intestine to the colon at the far end

    • From the colon it is excreted through the rectum. Undigested food and body wastes are eliminated through the anus, the opening of the rectum

  • Modified Ruminants

    • Modified ruminants are animals that have one stomach with three compartments
    • The compartments are as follows:
      • C1 -- similar to the rumen
      • C2 -- similar to the reticulum
      • C3 -- similar to the abomasum
    • Include the camel, alpaca, and hippopotamus

  • Ruminant Feeds

    • Eat roughages or forages
    • Forages include hay, pasture, and corn silage
    • Concentrates are often in the form of grains