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The Ruminant Digestive System - PowerPoint - PowerPoint by HC12091609944


									                          The Ruminant
                       Digestive System
            University of Kentucky College of Agriculture
Ruminant Digestive Systems
   Functions of the digestive system of
    animals include:
       ingestion (eating)
       chewing (mastication)
       swallowing (deglutition)
       absorption of nutrients
       elimination of solid wastes (defecation)
Ruminant Digestive Systems
   The digestive system changes food
    nutrients into compounds that are easily
    absorbed into the bloodstream.
Ruminant Digestive Systems
    Species like cattle, deer, sheep, horses,
     and rabbits that depend entirely on plants
     for food are classified as herbivores.
    Animals like dogs and cats that depend
     almost entirely on the flesh of other
     animals for food are classified as
Ruminant Digestive Systems
   Still others, like swine, birds, and humans
    that consume both flesh and plants are
    classified as omnivores.
Ruminant Digestive Systems
   Different species of animals have
    digestive systems adapted to the most
    efficient use of the food they consume.
   The anatomy and physiology of the
    digestive systems of herbivores,
    carnivores, and omnivores all differ.
Ruminant Digestive Systems
    Ruminants are those animals that contain
     a multi-chambered digestive system
     (polygastric) that allows the animal to
     gain the majority of their nutritional needs
     from forages and other roughages.
    Forage refers to grasses, roughages
     refers to other high-fiber food sources.
Ruminant Digestive Systems
   The digestive tract extends from the lips to
    the anus. It includes the mouth, pharynx,
    esophagus, stomach, and the small and
    large intestines.
   Accessory glands include the salivary
    glands, the liver, and the pancreas.
Ruminant Digestive Systems
   The length and complexity of the digestive
    system depends on the species.
   In herbivores, it is very long and complex.
       Rectum                                      Pharynx
                Cecum Kidney
  Ruminant Digestive Systems         Liver Esophagus

Anus                Picture of digestive system of cow

Colon                                         Reticulum
                             Rumen                        Gland
           Small Intestine               Omasum
Ruminant Digestive Systems
    The digestive system of ruminant animals
     includes the :
        Mouth - grasps the food
        Teeth - grind the food
             Ruminants have only one set of teeth in the front of
              the mouth (incisors), and two sets in the back
Ruminant Digestive Systems
    Tongue - covered with finger-like projections
     (papillae) that contain taste buds.
    Salivary glands - secrete saliva, that moistens
     food and is mixed with the food material to aid
     in swallowing.
Ruminant Digestive Systems
    Pharynx - funnels food into the esophagus,
     preventing food material from entering the
    Esophagus - food tube that leads from the
     mouth to the stomach.
Ruminant Digestive Systems
   At this point, ruminant animals have a
    multi-chambered “stomach”
       Reticulum - honeycomb-like interior surface,
        this part helps to remove foreign matter from
        the food material.
       The reticulum is also known as the stone trap
        or hardware stomach.
Reticulum - full
Reticulum - cleaned
Ruminant Digestive Systems
   Ruminant animals grasp mouthfuls of food
    and swallow it before it is chewed.
       They wrap their tongue around a mouthful of
        grass, clamp down their teeth, and pull to
        break the grass at its weakest point, and
Ruminant Digestive Systems
    Ruminants will“chew their cud” (regurgitate)
     their food material and then grind it with their
     molars at a time when the animal is resting.
    This is done until the food particles are small
     enough to pass through the reticulum into the
Ruminant Digestive Systems
   Since ruminant animals do not “chew”
    their food when it is taken in, at times
    foreign material like rocks, nails, small
    pieces of wire, can be swallowed.
Ruminant Digestive Systems
   While the animal is “chewing its cud”
    foreign particles that are heavy are allowed
    to “sink” in the reticulum, preventing many
    foreign particles from entering the rest of
    the digestive system.
   Once foreign material enters the reticulum,
    it stays there for the life of the animal.
Ruminant Digestive Systems
   If enough of this foreign material remains
    in the reticulum, it may cause damage and
    infection of the reticulum (hardware
Telephone Cord
Sponge taken
from digestive
system of an
Ruminant Digestive Systems
    Rumen - the organ that allows for bacterial
     and chemical breakdown of fiber.
       The rumen has a very thick, muscular wall.

       It fills most of the left-side of the abdomen
Ruminant Digestive Systems
    The  walls of the rumen contain papillae
     (that can be up to 1 cm. in length), where
     the bacteria that are used to breakdown
     fiber live.
    In some ruminants (dairy cattle) the rumen
     can have a capacity of 55-65 gallons!
    Fiber stimulates papillae to produce
     muscular waves, mixing the contents &
     removing gas.
Papillae in Rumen
Papillae in Rumen
Ruminant Digestive Systems
   Gas Expulsion occurs through periodic
    belching (eructation).
   Failure to belch can lead to bloat and can
    be fatal. This most often occurs after a
    sudden change in the diet.
Ruminant Digestive Systems
    Omasum - section that is round and
       “Grinds” the food material and prepares the
        food material for chemical breakdown.
       Also called the book stomach because of
        its leaf or page-like structures.
       It filters and absorbs water and salts.
Omasum - full
Ruminant Digestive Systems
    Abomasum - very similar to the stomach of
     non-ruminants; it is the “true” stomach.
       this is where the majority of chemical
        breakdown of food material occurs.
       mixes in digestive enzymes (pepsin,
        rennin, bile, etc.).
Abomasum – inside view
Ruminant Digestive Systems
    Small Intestine - where most of the food
     material is absorbed into the bloodstream
       Contains three sections:

          duodenum
          jejunum
          ileum
Ruminant Digestive Systems
    The  food material is continually
     squeezed as it is moved through the
     small intestine, becoming more solid.
    The majority of the food material
     absorption occurs in the duodenum and
     the jejunum.
Ruminant Digestive Systems
     Large Intestine - begins to prepare unused
      food material for removal from the body
        a portion of the large intestine in some
         animals contain pouches that may contain
         enzymes for further species-specific
         digestion (horses and rabbits (cecum)).
Ruminant Digestive Systems
      Colon - collects the unused food material that
       is to be removed from the body
      Rectum - “poop chute”
      Anus - opening through which the waste is
          Controlled by sphincter muscles, that also
           help protect the opening.
Ruminant Digestive Systems
    In conclusion, the rumen allows for
     bacteria to breakdown fiber, enabling
     ruminants to gain the proteins and
     energy from plant sources.
    Non-ruminant animals cannot obtain the
     nutritional value from most plant
     sources unless the food has been
     modified (ground, mashed, etc.)
Non-ruminants: Hindgut Fermenters

   Horse                             Small
                  Rectum   Cecum    intestine


    Small colon

Organs of non-ruminants
   Mouth, esophagus, stomach, liver, pancreas,
    gall bladder, and small intestine have similar
    functions as compared to monogastrics.

   Large Intestine
    ► Major difference between monogastrics and hind gut
      fermentors is the large intestine
    ► Large intestine is exceptionally large and complex
      compared to monogastrics and ruminants.
Organs of non-ruminants
   The large intestine of hind gut fermenters
    is analogous to the rumen in ruminants.
    ►Large, anaerobic fermentation vat.
    ►Microbes digest carbohydrates and convert to
        VFA’s  absorbed from large intestine and
        utilized by the animal.
Comparing Fermentation Strategies

Characteristics           Foregut (Ruminants)   Hindgut
Location of microbes:     Before stomach        After stomach
Are microbes digested?    Yes                   No
Source of energy:         VFA’s                 Food, VFA’s
Source of protein:        Microbes              Diet
Dietary flexibility       Low                   Higher
Throughput rate:          Slow: 40 – 50 hours   Faster by 3-5X
                          retention time
Efficiency of cellulose   High: 70 – 100!       Lower: 20 – 65%
Coprophagy in Rabbits
                VFA’s Caecum
               Fermentable fiber

   Rabbits produce two types of feces:
    Cecotropes are soft, edible, mucous
    covered packets of protein and vitamins.
   True feces are drier and contain
    undigested fiber.

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