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COLLECTION: GOAT HANDBOOK
ORIGIN: United States
DATE INCLUDED: June 1992
Extension Goat Handbook
This material was contributed from
collections at the National Agricultural Library.
However, users should direct all inquires about the
contents to authors or originating agencies.
DOCN 000000067
NO G-13
RESPIRATORY TRACT DISEASES
J. L. Ayers; Los Olivos, CA
S. B. Guss; Pennsylvania State U., University Park
Health and Disease Management
1 Clinical pneumonia in goats is almost invariably
preceeded by some event or set of circumstances commonly
referred to as stress. This very broad term, stress
includes such factors as weaning, long distance hauling,
weather factors including sudden temperature changes
or low nightime with high daytime temperatures, poorly
ventilated barns especially those heated in extremely
cold weather, overcrowding, malnutrition, feed changes,
parasitism and worming. The microorganisms (germs)
which produce the actual disease process are often
normal inhabitants of the respiratory tract. These
microorganisms are prevented from causing disease
by the normal animal's body defense mechanisms. The
relationship between the body and the microorganism
is sometimes a very delicate balance especially in
the very young animal. Stressing factors can tip the
balance in favor of the microorgansim and against
the young animal.
2 Barn ventilation in extremely cold
weather deserves special comment because it is often
overlooked. Warming a barn increases the relative
humidity, thus producing a stressful situation. Moisture
should never be allowed to accumulate on the walls,
ceilings and floors. The rule to follow, especially
in barns where the bedding is allowed to accumulate
and help maintain the warmth, is if the inside temperature
is 5F above the outside temperature, an exhaust fan
of adequate capacity to prevent moisture condensation
must be used. Goats kept in well ventilated barns,
which protect them from drafts and becoming wet, can
readily tolerate temperatures below -25F.
3 Acute Pasteurella Pneumonia In
the United States of America the most common cause
of pneumonia in goats is Pasteurella multocida and
P. hemplytica. It is an acute disease causing extreme
debilitation and often death. It occasionally has
a systemic form in which the gastro-intestinal tract
is the other primarily involved system.
4 In sheep and presumably in goats,
up to 400f normal animals contain one of the above
species of bacteria in their nasal passages.
5 Clinical Signs -- While herd outbreaks
do occur, individual cases also occur in goats. Morbidity
and mortality figures are not available for goats.
Depression, lack of appetite, mucopurulent (''pussy'')
discharge from the nose and occasionally the eyes,
occasional coughing (but not as consistent as in cattle
and sheep), fever (104 to 107F) are usually present.
Difficult or increased breathing is often not noticed
unless the animal is forced to exercise; in this case,
panting and coughing occurs.
6 Tissue Changes -- Small (petechial)
hemorrhages may be present on the lining of the body
cavities especially of the heart. The bronchiole lymph
nodes are usually swollen and hemorrhagic.
7 The most consistent and striking
change is seen immediately upon opening the chest
and completely reflecting the ribs, especially of
the right side. First there are marked adhesions of
the visceral and parietal pleura (chest cavity lining)
and pericardium. The heart and lung may be covered
with yellow-gray gelatinous or clotted fluid, fibrin
and fibrous connective tissue. This may completely
or partially hide the underlying apical and cardiac
lung lobe exposure of which reveals a very angry red
or purple appearance. The lobes are necrotic, friable
and often contain purulent exudate or even abscesses.
The fluid may be dirty-yellow and have a fetid odor.
When cut, the lungs may have a sharp line of demarcation
between the less angry looking (merely consolidated
or nearly normal) lung and the necrotic portion. A
dark hemorrhagic band of 2 to 3 millimeters may separate
the two zones. There are often necrotic cavitations
containing purulent exudate or necrotic debris.
8 Diagnosis -- Diagnosis is based
upon the history, signs and necropsy lesions and is
confirmed by isolation and identification of P. multocida
or P. hemolytica. Because of the presence of the organism
in normal animals, diagnosis cannot be made by culturing
the organism without the signs and lesions. Differentiation
from mycoplasma pneumonia (Mycoplasma mycoides subspecies
mycoides) can be tentatively assumed at necropsy by
the severe, angry appearance with marked necrosis
which is characteristic of caprine pasteurellosis.
Differentiation is important because treatment of
pasteurellosis and mycoplasmosis is different.
9 Prevention and Treatment -- Reducing
stressful circumstances or giving antibiotics preventively
when stress cannot be avoided, will help reduce the
severity and the incidence of the disease.
10 Penicillin and sulfamethazine
are approved for treatment by injection and sulfamethazine
is approved for oral administration.
11 However, oxytetracycline and the
long acting sulfonamide, sulfadimethoxine are also
effective against the organism. The major limitation
in using these antimicrobial drugs comes from the
very short but severe course of the disease. It is
difficult to detect, diagnose and treat before the
severe necrotizing tissue changes occur. However,
in an outbreak, an alert herdsman can detect additional
new cases early.
12 Acute Mycoplasmal Pneumonia The
mycoplasmal diseases of goats have taken some time
for scientists to sort, classify and understand. The
explanation is far beyond the scope of this article,
but suffice to say, in the US there is a rather common
disease characterized by acute pneumonia and arthritis.
This disease is caused by Mycoplasma mycoides ss mycoides
and is the most common cause of pneumonia in Arizona
goats. The organism with the same name, but with very
slight differences in growth characteristics (colony
size), is the one which causes the dreaded Contagious
Bovine Pleuropneumonia, eradicated from US cattle
in the 19th century.
13 The disease occurs primarily in
2 to 10 week old kids. Two Arizona outbreaks were
associated with the spring weather change of warm
days but continued cool (30 to 40F) nights. The acute
stage of severe disease and death loss lasted about
one week. Sick animals which survived were ill about
3 weeks. The morbidity (percentage of the herd affected)
was 70and the mortality was 36
14 Clinical Signs -- The most prominent
signs were swollen joints, especially the carpi and
stifles (front and rear knees) with or without lameness,
fever (106 to 108F) and dyspnea. Coughing is not consistent
unless ellicited by forced exercise or laryngeal pressure.
Swelling of the face or head is infrequently seen
and results from mandibular or atlanto-occipital joint
involvement.
15 Tissue Changes -- The lung changes
always occur on the right side and usually on the
left. They consist of red-purple consolidation of
the dependent or entire portions of the apical and
cardiac and occasionally the diaphragmatic lobes.
These portions are friable and moderate amounts of
mucopurulent exudate can often be squeezed from them.
Depending on the stage of the disease process, cut
sections of affected lung vary from dark reddish-purple
homogeneous tissue to a varigated color pattern of
hepatized to necrotic lobules separated by interlobular
edema or fibrosis. Occasionally thin walled abscesses
are present from which the organism can be isolated
in pure culture.
16 The copious yellow pleural exudate
often contain large quantities of soft fibrin lightly
adhering to the surfaces. Bronchial and mediastinal
lymph nodes are generally enlarged and on cut section,
very moist.
17 The major diarthrodial joints
are most often affected. The inflammatory reaction
varies from increased cloudy joint fluid with fibrin
clots to marked erosions of articular cartilage with
fibrosis of the joint capsule. Periarticular tissues
in acute cases were often edematous and congested,
with extensive fibrosis occurring in chronic cases.
18 Diagnosis -- As with acute pasteurellosis,
diagnosis is based on history, signs, necropsy lesions
and isolation of the causative organism. However,
the knowledge of which disease usually occurs in a
particular area is of practical importance while awaiting
laboratory confirmation. As previously stated, pasteurellosis
usually produces a much more severe or angry appearance
than mycoplasmosis; this is a subjective determination
and subject to error.
19 The organism will grow on ordinary
blood agar but many inexperienced technicians may
not keep the plate long enough to notice the tiny
areas of hemolysis in which a colony can only be seen
under magnification. Ideally a special mycoplasma
medium should be used, and if typical colonies are
found, sent by the diagnostic laboratory to one of
the few mycoplasma reference laboratories.
20 Prevention and Treatment -- Tylosin
is the drug of choice for mycoplasmosis. Prevention
is as difficult as preventing the change in the weather.
If outbreaks recur, the use of tylosin before an outbreak
occurs may possibly prevent it. In the face of severe
outbreaks, massive does of tylosin seem to be necessary
to appreciably affect the disease process. Two grams
of injectable tylosin given intravenously (slowly)
followed by 1 gram given subcutaneously twice daily
for 14 days appear to reduce the severity of an outbreak.
It must be stated that tylosin in any dose is not
approved for use in goats and inclusion in this section
cannot be construed as a recommendation of its use.
Indeed, at these high does, there may be a risk of
killing the animal. This must be weighed against the
possibility of losing the animal without this treatment
and needs to be discussed by the owner and the veterinarian.
The author gratefully acknowledges Dr. Dale Brooks
of the University of California at Davis as the initiator
of the massive dose system. The above dosage schedule
may not be the same as currently recommended by Dr.
Brooks.
21 Mycoplasmal Pneumonia of Spanish
and Angora Goats A pneumonia disease of Spanish and
Angora goats caused by Mycoplasma ovipneumoniae has
been reported from Texas. The time changes are apparently
quite similar to those produced by M. mycoides ss
mycoides.
22 Further, the affected animals
were subjected to extreme stress of inadequate handling,
inclement weather and disease. In two of the four
cases, only M. ovipneumoniae was isolated. The occurance
of the disease is associated with pasturing cows,
sheep and goats together; transmission may take place
from sheep to goats.
23 Chronic Progressive Pneumonia
This poorly documented pulmonary disease of goats
has many of the characteristics of Progressive Pneumonia
of sheep. It may be caused by a virus but it is complicated
by the common pneumonia producing bacteria. It is
found in breeding goats and invariably associated
with the stress of bad ventilation or close confinement
in dirty pens, especially kidding pens. Presumably
the kids acquire the etiologic agent early, perhaps
at birth from an infected mother. Each time the animal
is stressed, another episode of acute pneumonia and
more and more debilitation occurs; finally an acute
episode causes death, often not until 6 or 7 years
of age.
24 Clinical Signs -- During each
acute episode the animal is anorexic (won't eat),
stands by itself with its ears down, acts completely
lifeless. Auscultation of the lungs reveals some rales;
however, in the advanced case, so little air moves
through the lungs that the lung sounds are muffled.
Difficult breathing (dyspnea) is present and worsens
with repeated episodes. Hypoxia with blue tinting
of the mucous membranes of the mouth, vulva or sheath
continually worsen.
25 Tissue Changes -- If an animal
dies at a young age, lesions similar to but milder
than acute pasteurella pneumonia may be seen. As the
disease progresses, very small (miliary) foci containing
mucous or mucopurulent exudate occupy more and more
of the lung. Eventually the lung becomes essentially
filled by these foci and by old fibrous connective
tissue (scars) and abscesses. The lungs and bronchiolar
and mediastinal lymph nodes become 3 to 5 times as
heavy as normal. The animal has become extremely debilitated
and has very little body fat.
26 Diagnosis -- The history of chronic,
recurring pulmonary illness and necropsy findings
of chronic lung changes facilitate a diagnosis. Because
the disease in goats is not well documented, and the
real etiologic agent has not been identified, definitive
diagnosis is not yet possible.
27 Prevention and Treatment -- Treatment
has been unsuccessful. This fact gives evidence for
a viral etiology. Preventive measures should give
good results. All does with a chronic cough and having
acute pulmonary episodes should be culled from the
herd. Kidding barns and all other types of winter
housing should be kept clean and well ventilated.
RESPIRATORY TRACT DISEASES
COLLECTION;GOAT HANDBOOK
ORIGIN;United States
DATE_INCLUDED;June 1992
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