Medicine Lecture 4th Year 10-9-2016 Dr.Osamah Muwafk
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Principles of Alimentary Tract Dysfunction :
- The primary functions of the alimentary tract are the
prehension, digestion and absorption of food and water and
the maintenance of the internal environment.
- there are four major modes of alimentary dysfunction:
abnormality of motility, secretion, digestion or absorption.
A- Motor Function:
Disruption in gastrointestinal tract motility can result in:
1- Hypermotility or hypomotility
2- Distension of segments of the tract
3- Abdominal pain
4- Dehydration and shock
B- Secretory Function:
1- Diseases in which abnormalities of secretion occur are
not generally recognized in farm animals.
C- Digestive Function :
1- The ability of the alimentary tract to digest food depends
on its motor and secretory functions.
2- in herbivores, digestion depend on the activity of the
microflora that inhabits the forestomachs of ruminants or
cecum and colon of equidae.
3- The flora of the forestomachs of ruminants is capable of
digesting cellulose, of fermenting the end-products of
Medicine Lecture 4th Year 10-9-2016 Dr.Osamah Muwafk
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other carbohydrates to volatile fatty acids and converting
nitrogenous substances to ammonia and protein.
D- Absorptive Function :
1- Absorption of fluids and the dissolved end-products of
digestion may be adversely affected by increased motility
or by disease of the intestinal mucosa.
Manifestations of Alimentary Tract Dysfunction :
A- Abnormalities o f prehension, mastication and swallowing
1- Prehension
is the act of grasping for food with the mouth (lips,
tongue, teeth). It includes the ability to drink.
Causes of faulty prehension include:
a- Paralysis of the muscles of the jaw or tongue
b- Malapposition of incisor teeth due to: 1- inherited
skeletal defect (inherited displaced molar teeth,
inherited
mandibular
prognathism,
inherited
congenital osteopetrosis), 2- rickets
c- Absence of some incisor teeth
d- Pain in the mouth due to stomatitis, glossitis, foreign
body in mouth, decayed teeth, e.g. fluorosis
Medicine Lecture 4th Year 10-9-2016 Dr.Osamah Muwafk
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e- Congenital abnormalities of tongue and lips: inherited
harelip, inherited smooth tongue of cattle.
2- Mastication may be painful and is manifested by slow jaw
movements interrupted by pauses and expressions of pain
if the cause is a bad tooth, but in a painful stomatitis there
is usually complete refusal to chew.
3- Dysphagia is manifested by forceful attempts to swallow
accompanied initially by extension of the head, followed
by forceful flexion and violent contractions of the muscles
of the neck and abdomen.
4- causes of dysphagia and inability to swallow:
a- Foreign body.
b- tumor or inflammatory swelling in pharynx or
esophagus.
c- Painful condition of pharynx or esophagus.
d- Esophageal dilatation due to paralysis.
e- Esophageal diverticulum.
f- Esophageal spasm at site of mucosal erosion
(achalasia of cardia not encountered).
Medicine Lecture 4th Year 10-9-2016 Dr.Osamah Muwafk
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B- Drooling of Saliva and Excessive Salivation :
1- Drooling saliva from the mouth, distinct from frothing
such as occurs during convulsions, may be caused by
pain in the mouth and by an inability to swallow.
2- Excessive salivation is caused by stimulation of saliva
production by systemic toxins, especially fungal toxins,
or by hyperthermia.
C- Vomiting and Regurgitation :
1- Vomiting:
a- is the forceful ejection of contents of the stomach and
the proximal small intestine through the mouth and is
a complex motor disturbance of the alimentary tract. It
is
a
vigorously
active
motion
signaled
by
hypersalivation, retching and forceful contractions of
the abdominal muscles and diaphragm. It occurs in
two forms: projectile and true vomiting.
b- Projectile vomiting:
This is not accompanied by retching movements
and large amounts of fluid material are ejected with
little effort. It is almost always as a result of
overloading of the stomach or forestomach with
feed or fluid.
Medicine Lecture 4th Year 10-9-2016 Dr.Osamah Muwafk
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c- True vomiting
it occurs in monogastric animals like the dog and
cat, true vomiting is accompanied by retching
movements including contraction of the abdominal
wall and of the neck muscles and extension of the
head.
d- True vomiting is rare in farm animals.
e- True vomiting is not a feature of gastric disease in the
horse for two reasons, first the strong cardiac sphincter
inhibits the release of stomach contents, second the
soft palate and epiglottis combine to effect a seal
between the oral and nasal parts of the pharynx so that
any vomited stomach contents must be discharged
through the nasal cavities and not through the mouth.
f- Regurgitation is the expulsion through the mouth or
nasal cavities of feed, saliva and other substances that
have not yet reached the stomach.
g- Ruminants regurgitate rumen contents as part of
rumination but the material is not expelled from the
mouth nor into the nasal cavities.
h- Causes of vomiting and regurgitation include:
1- third-stage milk fever (loss of tone in the cardia)
Medicine Lecture 4th Year 10-9-2016 Dr.Osamah Muwafk
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2- arsenic poisoning (acute inflammation of the
cardia)
3- poisoning by plants including Eupatorium rugosum,
Geigeria spp., Hymenoxis spp., Andromeda spp.,
Oleander spp., Conium maculatum
4- veterinary administration of large quantities of
fluids into the rumen (regurgitation occurs while
the stomach tube is in place)
5- use of a large-bore stomach tube
6- cud-dropping: a special case of regurgitation
usually associated with abnormality of the cardia
D- Diarrhea, Constipation and Scant Feces :
a- Diarrhea: is the increased frequency of defecation
accompanied by feces that contain an increased
concentration of water and decrease in dry matter content.
The consistency of the feces varies from soft to liquid.
Common causes of diarrhea are:
1- Enteritis, including secretory enteropathy
2- Malabsorption, e.g. due to villous atrophy and in hypoc
uprosis (due to molybdenum excess)
3- Neurogenic diarrhea as in excitement
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4- Local structural lesions of the stomach or intestine,
including: ulcer, e.g. of the abomasum or stomach ,
tumor, e.g. intestinal ,Adenocarcinoma
5- Indigestible diet, e.g. lactose intolerance in foals
6- Carbohydrate engorgement in cattle
7- In some cases of ileal hypertrophy, ileitis, diverticulitis
and adenomatosis
8- Terminal stages of congestive heart failure (visceral
edema)
9- Endotoxic mastitis in cattle (splanchnic congestion)
10- Chronic and acute undifferentiated diarrhea in horses
11- Vagus indigestion in cows causes pasty feces but bulk
is reduced.
b- Constipation
is the decreased frequency of defecation accompanied
by feces that contain a decreased concentration of water.
The feces vary in consistency from being hard to dry and
of small bulk.
Common causes of constipation or scant feces are:
c- Diseases of the forestomach and abomasum causing
failure of outflow
d- Impaction of the large intestine in the horse and the sow
e- Severe debility, as in old age
Medicine Lecture 4th Year 10-9-2016 Dr.Osamah Muwafk
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f- Deficient dietary bulk, usually fiber
g- Chronic dehydration
h- Partial obstruction of large intestine
i- Painful conditions of the anus
j- Paralytic ileus
k- Grass sickness in horses
l- Chronic zinc poisoning in cattle
m- Terminal stages of pregnancy in cows
E- Ileus (A dynamic And Dynamic ileus) :
1- paralytic ileus or adynamic ileus is a state of functional
obstruction of the intestines or failure of peristalsis.
2- paralytic ileus there is loss of intestinal tone and motility as a
result of reflex inhibition.
3- can occur in acute peritonitis, excessive handling of viscera
during surgery, and prolonged and severe distension of the
intestines as in intestinal obstruction or enteritis.
4- Dynamic or mechanical ileus is a state of physical
obstruction.
Medicine Lecture 4th Year 10-9-2016 Dr.Osamah Muwafk
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F- Alimentary Tract Hemorrhage :
a- The main causes are:
1- Gastric or abomasal (rarely duodenal) ulcers
2- Severe hemorrhagic enteritis
3- Structural lesions of the intestinal wall, e.g. adenomatosis,
neoplasia
4- Infestation with blood-sucking nematodes, e.g. bunostomiasis
5- Local
vascular
engorgement
or
obstruction
as
in
intussusception and verminous thrombosis.
b- Hemorrhage into the stomach results in the formation of acid
hematin, which makes vomitus a dark brown color like
coffee grounds, and feces have a black or very dark brown,
tarry appearance (melena).
c- If the blood originates in the small intestine, the feces may be
brown-black.
d- Bleeding in colon or cecum, the blood is unchanged and
gives the feces an even red color.
e- Hemorrhage into the lower colon and rectum may cause the
voiding of feces containing or consisting entirely of clots of
whole blood.
Medicine Lecture 4th Year 10-9-2016 Dr.Osamah Muwafk
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G- Abdominal Pain :
The manifestations of abdominal pain vary with the species,
include:
1- Horses:
a- Acute_ pain: Pawing, flank-watching, rolling
b- Subacute pain: Lesser degree of flank watching, often
excessive pawing, lying down frequently without rolling,
stretching out as if to urinate, males may extrude the
penis, walking backwards, dog-sitting posture, lying on
back, impulsive walking
c- Peritoneal pain: Rigidity of the abdominal wall, pain on
palpation.
2- Cattle:
a- Acute pain: Downward arching of back with treading of
the hind feet, lying down (rolling is uncommon) . Calves
will lie down and bellow with severe abdominal pain, as
in abomasal torsion
b- Subacute pain, including peritoneal pain: Back arched
upwards, grunting on walking or lying down, grunting on
deep palpation of the abdomen, immobility.
Medicine Lecture 4th Year 10-9-2016 Dr.Osamah Muwafk
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H- Abdominal Distension :
1- Distension of the abdomen is a common manifestation of
disease of the alimentary tract.
2- Generally, abdominal distension associated with the
alimentary tract is caused by distension of viscera with gas or
fluid.