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Pasteurellosis
in Livestock
Randall
J Berrier, DVM
Staff Veterinarian
Technical Service
Pneumionic Pasteurellosis is a major cause
of economic loss in the cattle feedlot industry.
It is responsible for the largest cause of mortality in
feedlots in
North America
. The disease
causative organisms, Mannheimia
(formerly Pasteurella)
haemolytica and Pasteurella
multocida, are part of a complex group of bacteria and
viruses which together cause the syndrome “Shipping
Fever.” Fibrinous
pneumonia, caused by Mannheimia
haemolytica, is the most common lesion associated with
Bovine Respiratory Disease in feedlot cattle.
Pasteurellosis occurs most commonly in weaned calves from 6 to
8 months of age shortly after being weaned and placed in
feedlots in the fall. The
peak incidence of disease is within three weeks of arrival in
the feedlot. There
is usually a history of stressful events associated with
Shipping Fever which include:
Symptoms often start out vague with slight depression and
anorexia and can develop into more severe depression and
anorexia, fever, labored breathing, and rapid weight loss.
A cough may or may not be present and nasal discharge
starts out as mostly mucous and develops into a mostly
purulent (pus) discharge.
Catching the disease in the early stages is key to
successful treatment. If
the disease has progressed to advanced stages, poor response
to antibiotics can be expected due to the extent of greater
lung involvement (consolidation – resulting in loss of
functional lung tissue).
Morbidity (disease incidence) may reach 35% and case mortality
rates can be 5-10%. Population
mortality rates are estimated to be .75-1.0%.
These numbers may not be reliable though due to the
wide variation in the methods used to calculate disease
incidence. The
morbidity and mortality rates are probably higher since a lot
of cases go unreported or undiagnosed.
Prevention of Pasteurellosis and Shipping Fever involves
multiple steps. Calves
moved directly from ranches to feedlots, regardless of
vaccination status, had lower morbidity and mortality and
better weight gains than calves purchased from auction marts.
Vaccination against Mannheimia
haemolytica and Pasteurella
multocida, along with other respiratory vaccines, can be
of benefit.
Research has shown that effective artificial immunization of
cattle against Pasteurellosis is possible.
Antibodies to leukotoxin and certain bacterial surface
components appear to be important for disease immunity and
resistance. Colorado
Serum Company’s Mannheimia
Haemolytica-Pasteurella Multocida Bacterin contains
Mannheimia haemolytica
Types 1 and 2 and Pasteurella
multocida Type A. The
key to getting a good immunologic response to vaccination is
to vaccinate before imposing the stressful events such as
weaning and transportation to feedlots.
Colorado Serum Company recommends two doses initially, 2-4
weeks apart. Animals
vaccinated less than 3 months of age should be revaccinated at
weaning or at 4 to 6 months of age.
Mannheimia
Haemolytica-Pasteurella Multocida Bacterin is
also labeled for use in sheep and goats as pasteurellosis is
the most common form of bacterial pneumonia in these species
as well.
Ref.; Radostits, Gay, Blood and Hinchcliff; Veterinary
Medicine, 9th edition.
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