Transcript wf-r animal science 1

Digestive
Physiology of
Farm Animals
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Introduction
 Three (3) basic types of digestive systems:
► Monogastric – simple stomach.
► Ruminant – multi-compartmented stomach.
► Poultry – simple stomach, but very large and complex
large intestine
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Digestive Terminology
• Digestion- the process of breaking feed
down into simple substances that can be
absorbed by the body.
• Digestive System- the parts of the body
involved in chewing and digesting feed.
• Absorption- the process of taking digested
parts of feed into the bloodstream.
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Digestive Terminology
• Ruminants- animal that have a stomach
that is divided into several parts.
– Cattle, goats and sheep are examples of ruminant
animals.
– Ruminant animals can digest larger amounts of
roughage material compared to nonruminants.
– Ruminants do not chew their food completely. Some
food is swallowed and then rechewed later through a
process known as “chewing the cud.” This process is
also called rumination.
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Digestive Terminology
• Nonruminant- animals that have a
monogastric or single compartment
stomach.
– Horses, pigs, dogs, cats, and poultry are
examples of monogastric animals.
– Non-ruminants cannot eat and digest as much
roughage as ruminants.
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Types of Digestive Systems
Monogastrics
Dogs
Pigs
Ruminants
Beef Cattle
Dairy Cattle
Poultry
Chickens
Turkeys
Cats
Horses
Human
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Goats
Sheep
Deer
Ostrich
Basic Functional
Anatomy of the
Digestive System
– Monogastrics
(Nonruminant) –
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Digestive Tract - Pig
Liver
Pancreas
Cecum
Rectum
Esophagus
Stomach
Duodenum
Small intestine
(jejunum, ileum)
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Colon
Digestive Tract - Pig
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Organs of the Digestive System
– Monogastrics –
 Mouth
► Function: Bites & chews food; breaks down food in smaller
particles; Saliva present in mouth contains enzymes which
speed up digestive process
► Description: Beginning of digestive tract; includes teeth & tongue
 Esophagus
► Function: Guides food from mouth to stomach with involuntary
muscular contractions
► Description: Pinkish-grey colored muscular tube next to
trachea; guides food from mouth to the stomach
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Organs of the Digestive System
– Monogastrics –
 Stomach
► Function: Enzymes act on feed; churns & mixes feed
► Description: A “U” shaped, pinkish/white colored sac
connected to the esophagus
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Organs of the Digestive System
– Monogastrics –
 Small Intestine
► Function: Partially digested feed is mixed with bile,
pancreatic juice & intestinal juice; most food nurtients
are absorbed from the villi (small hairlike projections)
in the small intestine
► Description: Long, coiled tube
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Organs of the Digestive System
– Monogastrics –
 Cecum
 Function: Serves little to no function for most animals; Horses,
rabbits & guinea pigs have an enlarged cecum that uses
microbial action to break down roughages
 Description: A blind pouch located between the small & large
intestines
 Large Intestine
► Function: Absorbs water & adds mucus to the undigested feed to
form feces
► Description: Coiled tube, shorter in length, but larger in diameter
than the small intestine
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Organs of the Digestive System
– Monogastrics –
• Anus
– Function: Excrete waste
– Description: End of the digestive tract
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Basic Functional
Anatomy of the
Digestive System
– Ruminants –
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Digestive Tract – Beef Cattle
Small intestine
Rectum
Rumen
Pancreas
Omasum
Esophagus
Large
intestine
Reticulum
Cecum
Liver
Gall
bladder
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Abomasum
Digestive Tract – Beef Cattle
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Organs of the Digestive System
– Ruminants –
Mouth, esophagus, small intestine, cecum, large
intestine, and anus have functions similar to
monogastrics (nonruminants).
 Stomach
► Structure and function of the stomach is the major
difference between monogastrics and ruminants.
► Multi-compartmented stomach – rumen, reticulum,
omasum, abomasum.
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Parts of the Ruminant Stomach
 Rumen:
► Large, anaerobic fermentation vat.
Rumen Capacity
Species
Normal capacity
Maximum capacity
Cow (1000 lb)
25-30 gallons
55-60 gallons
Ewe (150 lb)
3-5 gallons
5-10 gallons
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Parts of the Ruminant Stomach
 Rumen (continued):
► Function: Bacteria change large amounts of
roughages into amino acids
► Description: Large white/grey colored sac on the left
side of the animal
► Largest section of the stomach
► Interior lining resembles a carpet
► The rumen and reticulum make up 85% of stomach capacity
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Parts of the Ruminant Stomach
 Rumen (continued):
► Lined with millions of
papillae (short projections
on wall of rumen) needed
for absorption.
 “Shag carpet” appearance
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Parts of the Ruminant Stomach: FYI
 Rumination:
► Ruminants are well known for “cud chewing”.
► Rumination involves:
 Bolus of previously eaten foodstuff carried back into the
mouth.
 Fluid in bolus is squeezed out with the tongue and
reswallowed. May be up to 6-7 times per Bolus
 Bolus is rechewed and reswallowed.
► Rumination may occupy about 1/3
of a ruminant’s day
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Parts of the Ruminant Stomach: FYI
► Fermentation of foodstuffs in the rumen generates
enormous quantities of gas.
 30-50 liters per hour in adult cattle.
 5-7 liters per hour in adult sheep or goats.
► Belching is how ruminants get rid of fermentation
gases:
 Anything that causes a hindrance to belching can be life
threatening.
 Bloating can result in death from asphyxiation.
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Parts of the Ruminant Stomach
 Reticulum:
► Function: Take in liquids that soak food for microbial
digestion
► Description: White/grey colored sac connected to the
rumen on the left side of the animal
► Interior lining resembles a honeycomb pattern
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Parts of the Ruminant Stomach
 Reticulum (continued):
► Lining has a honeycomb
structure.
 Catches and holds hardware
consumed by animal.
 Hardware can be removed with
rumen magnate.
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Telephone Cord
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Wire
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Ruminant Stomach
esophagus
reticulum
rumen
omasum
abomasum
Together the Rumen and the Reticulum make up over 85
percent of the Rumen Stomach
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Parts of the Ruminant Stomach
 Omasum:
► Function: Contains papillae
responsible for grinding
roughage
► Description: Round, muscular
part of the stomach with
many layers of tissue that
squeezes feed & removes
some liquid
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Parts of the Ruminant Stomach
 Abomasum:
► The true, glandular stomach
► Function: Enzymes and gastric
juices act on feed
► Only functional part of the stomach
when ruminants are born
► Description: Elongated sac at the
base of the stomach
► Interior lining is the smoothest of all
stomach parts
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Ruminant & Nonruminant
Accessory Organs
• Liver
– Function: Produces bile that acts on fats
– Description: Dark brown structure made of
several lobes
• Largest gland in the body; located under the
stomach
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Ruminant & Nonruminant
Accessory Organs
• Pancreas
– Function: Produces digestive enzymes
– Description: Elongated reddish colored organ
that lies against the stomach
• Gall Bladder
– Function: Produces bile that aids in digestive
processes
– Description: Sac like structure filled with
greenish fluid; located on the liver.
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Basic Functional
Anatomy of the
Digestive System
– Poultry –
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Digestive Tract - Poultry
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Digestive Tract - Poultry
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Organs of the Digestive System
– Poultry –
Specialized Organs in Poultry
 Mouth
► Function: Pecks & takes in feed; NO TEETH
► Description: Yellowed pointed structure (beak)
 Esophagus
► Function: Guides food from break to crop
► Description: Muscular tube shaped structure
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Organs of the Digestive System
– Poultry –
 Crop
► Out-pocketing of the esophagus that provides storage
for consumed food.
► Foodstuffs moistened and softened (little if any
digestion).
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Organs of the Digestive System
– Poultry –
Specialized Organs in Poultry (continued)
 Proventriculus
► Function: True stomach of chicken, but serves no real function
► Description: A wider section of the digestive system compared to
the esophagus
 Gizzard
► Function: Feed is crushed & mixed with digestive juices; contains
grit & gravel to assist in crushing feed particles
► Description: Oval shaped muscle that is purplish in color; located
between the proventriculus & small intestine
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Organs of the Digestive System
– Poultry –
• Grit that is
commonly added
to chicken feed to
aid in digestion.
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Organs of the Digestive System
– Poultry –
• Feed has to be very high in nutrients due
to the rapid movement through the
digestive system.
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Organs of the Digestive System
– Poultry –
Specialized Organs in Poultry (continued)
*Liver, Small Intestine & Large Intestine have the same
function as Ruminants & Nonruminants!
 Ceca
► Function: Contain soft, undigested feed, but function is
unknown
► Description: Unlike other animals, poultry have 2 ceca.
Located between small & large intestines & are “blind”
pouches- each are approx. 7” in length
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Organs of the Digestive System
– Poultry –
 Cloaca
► Function: Digestive & reproductive tracts
combine & prepare for excretion of waste or
eggs
► Description: Enlarged part of digestive tract
located just before the vent
 Vent
► Function: Excrete solid (feces) & liquid (urine)
waste
► Description: External opening & the end of the
digestive tract
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Specialized Poultry Organs
Crop
Gizzard
Vent
Proventriculus
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Summary
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Summary
 There are three (3) basic types of digestive
systems in farm animal species.
► Monogastric
► Ruminant
► Poultry
 The type of digestive system influences the
dietary foodstuffs the animal can effectively
utilize.
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Digestive Tract Capacities
Sheep/Goats
Cattle
Swine
Horses
5-10 gal
55-60 gal
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Reticulum
1.5 qt
3-4 gal
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Omasum
1 pt
1-2 gal
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1.5 qt
3-4 gal
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2 gal
2-3 gal
2.5 gal
17-18 gal
2.5 gal
12-15 gal
85-90 ft
130 ft
60 ft
70 ft
1.5 gal
10 gal
3 gal
30-35 gal
Rumen
Abomasum
Stomach
Small intestine
Small intestine
length
Large intestine
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THE END
Any
questions?
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