Transcript The Ruminant Digestive System

Daily Food for
Thought
Trace and name
the parts of the
monogastric
digestive system.
Monogastric Digestive System
Mouth
Esophagus
Stomach
Duodenum
Jejunum
Ileum
Cecum
Colon
Rectum
Anus
Ruminant Digestive Systems
Learning Target:
I can trace identify the parts of the ruminant
digestive system and describe the functions of each.
The Ruminant
Digestive System
Ruminant Digestive Systems
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Functions of the digestive system of
animals include:
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ingestion (eating)
chewing (mastication)
swallowing (deglutition)
absorption of nutrients
elimination of solid wastes (defecation)
Ruminant Digestive Systems
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The digestive system changes food
nutrients into compounds that are easily
absorbed into the bloodstream.
Ruminants
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2.8 billion domesticated ruminants
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Cattle, sheep, deer, elk, bison
Pregastric fermentation
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Ability to chew cud at frequent intervals
distinguishes true ruminant from other foregut
fermenters
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Kangaroo, colobine monkey are not true ruminants
Four compartment stomach
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Reticulum
Rumen
Omasum
Abomasum
Ruminants vary in size and habitat
Ruminant Digestive Systems
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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
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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.
Classification of Ruminants by
Feeding Preference
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Classes of ruminants
 Concentrate selectors
 Intermediate feeders
 Roughage grazers
Concentrate Selecting Species
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Properties
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Evolved early
Small rumens
Poorly developed omasums
Large livers
Limited ability to digest fiber
Classes
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Fruit and forage selectors
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Very selective feeders
Duikers, sunis
Tree and shrub browsers
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Eat highly lignified plant tissues to extract cell solubles
Deer, giraffes, kudus
Intermediate Feeding Species
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Properties
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Seasonally adaptive
Feeding preference
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Prefer browsing
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Moose, goats, elands
Prefer grazing
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Sheep, impalas
Roughage Grazing Species
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Properties
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Most recently evolved
Larger rumens and longer retention times
Less selective
Digests fermentable cell wall carbohydrates
Classes
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Fresh grass grazers
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Roughage grazers
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Buffalo, cattle, gnus
Hartebeests, topis
Dry region grazers
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Camels, antelope, oryxes
Ruminant Digestive Systems
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The length and complexity of the digestive
system depends on the species.
In herbivores, it is very long and complex.
Pancreas
Rectum
Pharynx
Liver Esophagus
Cecum Kidney
Ruminant Digestive Systems
Teeth
Anus
Picture of digestive system of cow
Tongue
Colon
Reticulum
Small Intestine
Rumen
Omasum
Abomasum
Salivary
Gland
Ruminant Digestive Systems
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The digestive system of ruminant animals
includes the :
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Mouth - grasps the food
Teeth - grind the food
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Ruminants have only one set of teeth in the front of
the mouth (incisors), and two sets in the back
(molars).
Ruminant Digestive Systems
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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
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Pharynx - funnels food into the esophagus,
preventing food material from entering the
lungs.
Esophagus - food tube that leads from the
mouth to the stomach.
Ruminant Stomach
Anatomy:
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Reticulum
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Rumen
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Omasum
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Abomasum
Ruminant Digestive Systems
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At this point, ruminant animals have a
multi-chambered “stomach”
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Reticulum - honeycomb-like interior surface,
this part helps to remove foreign matter from
the food material.
Reticulorumen
Although
structurally they
appear as a single
continuous
compartment,
functionally they are
distinctly different
Reticulum - full
Reticulum - cleaned
Reticulum
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Honeycomb lining
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No secretions
Formation of food
bolus
Regurgitation
initiated here
Collects hardware
(nails, wire)
Ruminant Digestive Systems
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Ruminant animals grasp mouthfuls of food
and swallow it before it is chewed.
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They wrap their tongue around a mouthful of
grass, clamp down their teeth, and pull to
break the grass at its weakest point, and
swallow.
Ruminant Digestive Systems
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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
rumen.
Ruminant Digestive Systems
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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
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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
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If enough of this foreign material remains
in the reticulum, it may cause damage and
infection of the reticulum (hardware
disease).
Telephone Cord
Wire
Sponge taken
from digestive
system of an
animal
Ruminant Digestive Systems
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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
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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!
Rumen
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Digestion and
fermentation vat
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Contains anaerobic
microbes (25-50 billion
bacteria/mL fluid)
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Also protozoa, fungi
Produce VFA, protein
Papillae lining
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40-50 gallons
No secretions
Increase surface area
Absorption of VFA
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Passive diffusion
Papillae in Rumen
Papillae in Rumen
Ruminant Digestive Systems
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Omasum - section that is round and
muscular.
 “Grinds” the food material and prepares the
food material for chemical breakdown.
Omasum
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Laminae/manyply lining
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Reduces particle size
Absorption of water
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Muscular folds
No secretions
~60% removed
Absorption of VFAs
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~2/3 of VFAs entering or
10% of total produced
Prevents buffering of the
abomasum
Omasum - full
Ruminant Digestive Systems
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Abomasum - very similar to the stomach of
non-ruminants.
 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
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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
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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)).
Large Intestine
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Fermentative digestion
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Bacteria similar to rumen, but no protozoa
Digestion in colon may account for as much as:
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Only important in conditions that increase the amount of
fermentative carbohydrate entering the large intestine
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27% of cellulose digestion
40% of hemicellulose digestion
10% of starch digestion
Increased rate of passage of forages
High grain diets
May account for as much as 17% of total VFA absorption
VFAs are efficiently absorbed, but primarily used as energy
source for large intestinal mucosa cells
Large Intestine
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Absorption of ammonia-N
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May account for as much as 30 to 40% of the net
transport of N into body fluid
Absorbed N may be used for:
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Synthesis of nonessential amino acids
Recycling of N to the rumen
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Regulated by:
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Important on low protein diets
Increased by increasing N concentration of diet
Decreased by increasing the amount of carbohydrate
fermented in the large intestine
Mineral absorption
Water absorption
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90% of water entering the LI is absorbed
Ruminant Digestive Systems
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Colon - collects the unused food material that
is to be removed from the body
Rectum - “poop chute”
Anus - opening through which the waste is
removed.
 Controlled by sphincter muscles, that also
help protect the opening.
Ruminant Digestive Systems
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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.)
index
Ruminant Digestive Systems
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Ruminants are those animals that contain
a multi-chambered digestive system
(_________) that allows the animal to
gain the majority of their nutritional needs
from _______ and other _____________.
Ruminant Digestive Systems
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At this point, ruminant animals have a
multi-chambered “__________”
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_________ - honeycomb-like interior surface,
this part helps to remove foreign matter from
the food material.
Ruminant Digestive Systems
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______ - the organ that allows for bacterial
and chemical breakdown of fiber.
 The _____ has a very thick, muscular wall.
 It fills most of the _______ of the abdomen
Ruminant Digestive Systems
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_______ - section that is round and muscular.
 “______” the food material and prepares
the food material for chemical breakdown.
Ruminant Digestive Systems
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__________ - very similar to the stomach of
non-ruminants.
 this is where the majority of chemical
breakdown of food material occurs.
 mixes in digestive __________ (pepsin,
rennin, bile, etc.).