The publications in this collection do
not reflect current scientific knowledge
or recommendations. These texts
represent the historic publishing
record of the Institute for Food and
Agricultural Sciences and should be
used only to trace the historic work of
the Institute and its staff. Current IFAS
research may be found on the
Electronic Data Information Source
site maintained by the Florida
Cooperative Extension Service.
Copyright 2005, Board of Trustees, University
Veterinary Medicine Extension
t, oi Florida k
Eliminate Brucellosis From Beef Herds
Florida Cooperative Extension Service / Institute of Food and Agricultural Sciences /University of Florida /John T. Woeste, Dean
Brucellosis, also known as Bang's Disease, is an infectious, highly
contagious disease of cattle caused by the bacteria, Brucella
abortus. The disease primarily strikes cattle and the American
buffalo. Brucellosis sometimes infects horses, dogs, swine, and
humans; however, brucellosis is considered to be a "dead-end
disease" in these species. Bang's is primarily a disease of the
female, the cow. Bulls can be infected but they do not readily
spread the disease. The brucellosis organism localizes in the
testicles of the bull and produces an orchitis (inflammation of the
testicles), whereas, in the female the organism localizes in the
udder, uterus, and lymph nodes adjacent to the uterus. The
infected cows exhibit symptoms which may include abortion during
tne last third of pregnancy, retained afterbirth, and weak calves
at birth. The infected cows usually abort only once and deliver
weak calves from then on. Some infected cows will not exhibit any
clinical symptoms of the disease and give birth to normal calves
at birth. The brucellosis organism is shed by the millions in the
afterbirth and fluids associated with calving and aborting. One
infected cow, at calving, can spread millions of brucella bacteria
and is a threat to your herd. Heifer calves born to infected cows
may become infected at birth and remain undetected until they reach
puberty. Hence, heifer calves born to infected cows are considered
to be "a high risk" and should not be kept for breeding animals.
The brucella organisms are difficult to control while they are in
the animal; there is no economical cure. But once outside the
animal, the brucella bacteria are easily killed by sunlight, high
*Extension Veterinarian, College of Veterinary Medicine, University of Florida, Gainesville 32611.
-temperatures, drying, and disinfecting. For this reason, pastures
in Florida can be safely restocked within several months following
the removal of all infected cattle, aborted fetuses, afterbirths
and dead calves.
Serological blood tests are used to detect the presence and the
level of brucella antibodies in cattle. Antibodies are produced
by the body to exert a defensive action against the Brucella
abortus bacteria. The level of antibody circulating in the blood
is referred to as the brucellosis titerr". This term titerr) is
commonly used in questions or statements referring to brucellosis
test results. ie. "Did she have a titer?,". The level of the
brucellosis titer in the blood will help classify the animal as a
negative animal, a suspicious animal, or positive reacting animal.
Other commonly used words or phrases used when referring to
brucellosis test results are "banging out" or "reactor". Did she
"bang out"; asking if the animal possessed an antibody level high
enough to consider her as infected. "Was she a reactor?"; asking
if the animal reacted positive to the serological test. The
brucellosis blood tests used in Florida are actually a battery of
tests used in sequence. The first test routinely conducted is the
"Card" test. The card test is a quick screening test that
determines if the animal is a "reactor". Reactors to the card test
are official "REACTORS"; they reacted positive to the test and will
be handled as brucellosis infected animals. However, occasionally
"reactors" are positive to things other than brucellosis
infections. Additional tests such as the BAPA test, the Rivanol
test, and the Complement Fixation test are need to determine if the
animal is actually infected. If the blood from a particular animal
reacts positive to the card test, then a "BAPA" test is conducted
on the same blood sample; if the BAPA test is positive, then the
blood sample is subjected to a "Rivanol" test. A "Complement
Fixation" test is conducted on the Rivanol positive samples. With
this "battery" of tests, a presumptive diagnosis of brucellosis is
made or rejected. "Reactors", whether infected with brucellosis
or not, should be removed from the herd and slaughtered; if non-
infected reactors remain in the herd, they will only tend to add
confusion to the eradication program.
Brucellosis blood tests are used first to help make a diagnosis of
brucellosis in a herd and second to classify each animal within
that herd as having a negative titer, a suspicious titer, or a
positive titer. Negative and positive titered (reactor) animals
are pretty much cut-and-dried, but the suspicious titered animal
opens a new ball game. To understand a suspicious titered animal,
one must understand the titer development in both an infected
animal and a brucellosis vaccinated animal.
In an animal that is free of brucellosis infection and has not been
vaccinated, the titer level will be zero or negative. However, if
that animal becomes infected with brucellosis the titer would rise
rapidly, plateau, and stay high.
IN BRUCELLOSIS INFECTION:
THE ANTIBODY LEVEL ..... RISES RAPIDLY
..... STAYS HIGH
EXPOSED TO AG'S
In contrast, if a non-infected animal was to be vaccinated, the
titer would rise rapidly, peak out, begin to decrease, and return
THE ANTIBODY LEVEL ... ALSO RISES, BUT
... RETURNS TO 0
TIME ------ -
If an animal has a titer that is between zero and the typical high
titer of an infected animal, the question arises: "is this an
infected animal with a rising titer or is this a vaccinated animal
showing a titer that is very slow to return to zero"? This animal
is designated as having a "suspicious" titer and will probably need
retesting at a later date.
VACCINATION TITER ?
OR DISEASE TITER ?
I4 TIME ------
If the titer continues to rise the animal will be classified as an
infected animal. If the titer decreased or returned to zero, the
animal would be classified as a brucellosis free vaccinated animal.
In addition to the blood tests, more information may be needed to
make an accurate diagnosis of brucellosis. The required
information would include the vaccination history of the herd, the
origin of the herd or a specific animal in the herd, the infection
status of the adjoining herds, the presence of brucellosis symptoms
in the herd, the previous brucellosis test results, the calving
history, and management practices used in the herd.
If a herd is found to be infected with brucellosis, the herd is
placed under official "quarantine". As soon as you are notified
of the quarantine, it is a good idea to contact a USDA or State
Regulatory Veterinarian. The Regulatory Veterinarian will conduct
an investigation and make recommendations to eradicate brucellosis
from the herd.
ERADICATING BRUCELLOSIS FROM A HERD:
Basically, 3 management tools will be needed to clean up the
infected herd. The 3 tools are calving management, vaccination,
and testing with removal of reactors. These three tools must be
used together to clean up an infected herd rapidly and
economically. Always remember that millions of the brucella
organisms are shed in the afterbirth and fluids associated with
calving and aborting. The infected cow will begin to shed the
organisms from the uterus beginning 14 days before calving or
aborting and may continue to shed for as long as 60 days after
calving or aborting; a period that may last 75 days.
SHEDDING OF THE BRUCELLOSIS ORGANISM:
STARTS ABOUT 14 DAYS BEFORE .....
& ENDS ABOUT 60 DAYS AFTER
CALVING OR ABORTING.
Hence, when calving-out an infected herd, you could have the
shedding of brucellosis organism for 75 days longer than your
calving period. If you had a 180 day calving period, you could be
having a 255 day exposure to brucellosis. In a herd with year-
round calving, you could have year-round exposure to brucellosis.
The only way to shorten the length of the exposure period would be
to shorten the calving period. When you shorten the calving period
you reduce the disease challenge (exposure) of the herd to
brucellosis organisms shed from infected animals while calving.
REDUCE THE DISEASE CHALLENGE
WHEN YOU SHORTEN THE CALVING SEASON, YOU HAVE CALVING MANAGEMENT,
THE FIRST TOOL.
The second tool needed to clean up an infected herd is a
brucellosis vaccination program; one that includes vaccination with
Strain-19 vaccine and possibly whole herd vaccination. Vaccination
will increase the resistance level to brucellosis in the animal:
however, vaccination does not afford the animal total protection
from the disease.
RISE IN RESISTANCE DUE TO VACCINATION
The rise in resistance stimulated by any vaccine can be overwhelmed
by a continuous high exposure to the disease; the disease challenge
rises and remains high. Animals vaccinated with Strain-19
brucellosis vaccine are not exempted; they can become infected if
they are subjected to a continuous high brucellosis exposure.
A HIGH RESISTANCE LEVEL CAN BE OVERWHELMED BY A
EXTREMELY HIGH RISE IN THE DISEASE CHALLENGE.
But, any brucellosis vaccinated animal that becomes infected will
shed fewer brucellosis organisms at calving, thereby reducing the
exposure to the herd.
Whole herd vaccination requires that all females in the herd over
4 months of age be vaccinated with Strain-19 vaccine. Routine
calfhood vaccination in an infected herd requires that heifer
calves between 4 and 8 months of age be vaccinated. Adult
vaccination is the vaccination of all females over 8-months of age;
therefore, whole herd vaccination includes a calfhood vaccination
program and an adult vaccination program. (Often the whole herd
vaccination program is erroneously referred to as adult vaccination
or "AV"). The single most important advantage of whole herd
vaccination is a rapid increase in resistance for the herd; all
females over 4 months-of-age are vaccinated, resulting in a 100%
vaccinated herd! Other advantages of whole herd vaccination are
1. slowing the spread of brucellosis....so fewer reactors are
removed, 2. reducing or stopping abortions....so more calves go to
market, and 3. preventing the re-introduction of brucellosis into
the herd. Probably the most asked question concerning whole herd
vaccination is: "should I whole herd vaccinate"? With few
exceptions, the answer is: "if your herd is presently infected and
it is not 100% vaccinated, then you need to whole herd vaccinate"!
The third tool needed to clean up a brucellosis infected herd is:
TESTING and the REMOVAL OF INFECTED ANIMALS. Testing with the
removal of infected animals is another method to reduce the disease
challenge to the herd. The greatest misunderstanding when dealing
with the test and removal tool is the TESTING INTERVAL. The
testing interval refers to how often a herd must be tested or how
many times a year the herd will be tested. The testing interval
actually depends upon the first and second tools needed to clean
up an infected tool. It depends upon the calving management and
the herd vaccination status. The testing interval for a 100%
VACCINATED HERD (all females, calves & adults, are vaccinated) WITH
A CALVING PERIOD OF LESS THAN 120 DAYS will require a minimum of
2 tests per year; one before the calving period begins and one
after the calving is over.
TEST INTERVAL FOR A
100% VACCINATED HERD wIT
A CALVING PERIOD LESS THAN 120 DAYS.
ONE BEFORE CALVING 2 cTS ER.
s OWE AFTER CALVING
MINIMUM OF 2 TESTS PER YEAR.
The required testing for a 100% VACCINATED HERD WITH A CALVING
PERIOD OF LESS THAN 365 DAYS, BUT GREATER THAN 120 DAYS, includes
1 test before calving; 1 test every 60 days during the calving
period; and 1 test after the calving period ends.
TEST INTERVAL FOR A
100% VACCINATED HERD WIT A
CALVING PERIOD OF LESS THAN 365 DAYS .....
.... BUT GREATER THAN 120 DAYS.
ONE BEFORE CALVING
ONE AFTER CALVING
The testing interval required for a 100% VACCINATED HERD WITH YEAR-
ROUND CALVING is at least every 60-90 days or 4-6 times per year.
TEST INTERVAL FOR A
100% VACCINATED HERD WITH
TEST EVERY 90 DAYS .....
..... MINIMUM OF 4 TESTS / YEAR
In contrast, the testing interval for a NON-VACCINATED or a
PARTIALLY VACCINATED HERD, regardless of the length of the calving
period is a test every 30-60 days; 6-12 tests per year.
TEST INTERVAL FOR A
NON-VACCINATED OR PARTIALLY VACCINATED HERD
REGARDLESS OF THE LENGTH OF THE CALVING PERIOD
TEST 6-12 TIMES PER YEAR.
Hence, the testing interval depends upon the vaccination status of
the herd and the length of the calving period.
IF AN INFECTED HERD OWNER HAS:
1. CALVING MANAGEMENT .... WHICH REDUCES THE EXPOSURE TO
BRUCELLOSIS IN A HERD.
2. INSTITUTES A VACCINATION PROGRAM .... WHICH INCREASES THE
RESISTANCE LEVEL OF THE HERD.
3. BEGINS TO TEST AND REMOVE REACTORS AT THE RECOMMENDED
INTERVALS .... WHICH ALSO REDUCES EXPOSURE, AND
4. PROVIDES A DIAGRAM OF THE RANCH .... so THAT EVERYONE
INVOLVED CAN UNDERSTAND THE MANAGEMENT PROBLEMS;
YOU HAVE A HERD PLAN FOR THE ERADICATION OF BRUCELLOSIS FROM THE
In addition to eradicating the disease, the "Herd PLan" provides
a systematic approach for keeping a "comfortable spread" between
the brucellosis RESISTANCE LEVEL and the DISEASE CHALLENGE LEVEL
in the herd.
A COMFORTABLE SPREAD BETWEEN THE RESISTANCE LEVEL
AND THE LEVEL OF THE DISEASE CHALLENGE.
Eventually, the herd must undergo 2 whole-herd negative tests
before it will be considered for release from quarantine; the
second whole-herd negative test must have been conducted at least
180 days after the last reactor was removed from the herd. In
Florida, a mandatory post-quarantine test must be conducted 6
months after the release from quarantine to assure that all of the
disease has been removed from the herd. Failure to conduct this
test will require that the herd again be placed under quarantine.
The whole-herd tests must include all non-neutered cattle 6 months-
of-age and older, including cattle that have been officially
vaccinated for at least 6 months. Periodic whole-herd Bang's
testing is necessary to insure that brucellosis has not been
introduced or reintroduced into a clean herd. If a herd has had
at least 2 consecutive negative herd blood tests between 10 and 14
months apart; that herd is eligible for CERTIFICATION. The "post-
quarantine" test conduced 6 months after release from quarantine
MAY qualify the herd for "Certified Brucellosis Free" status,
provided that the herd is negative and the test is performed within
10 to 14 months of the initial negative test. Certification is not
automatic; certification requires, in addition to the negative
test, that the herd owner APPLY for the "Certified Brucellosis
Free" status at the State Veterinarian's Office in Tallahassee.
Once certified, a herd must have an annual negative whole-herd test
between 10 and 14 months after the certification anniversary date
to be eligible for RE-CERTIFICATION.
UNIVERSITY OF FLORIDA
3 1262 05128 5772
To put it another way; "herd testing every 10 to 14 months provides
an excellent monitoring tool to insure that brucellosis has not
been introduced into a herd; if the whole-herd tests remain
negative, then the herd is eligible for continuous Brucellosis
Certified Free status".
Many cattlemen think that "Certifying" a herd is for movement
purposes only; but in reality, certification & re-certification
provides the herd owner with a disease monitoring tool and sends
an "OFFICIAL MESSAGE" to the United States beef industry that
Florida beef herds are being periodically checked to insure that
brucellosis is not being reintroduced back into clean herds and the
eradication program is on track.
To insure continued movement of cattle, the beef producer should
consider certifying and re-certifying their herds, but we must
always keep in mind that "BRUCELLOSIS IS AN INFECTIOUS DISEASE."
We need to address it as such and promote the "Brucellosis
Certified Free Herd" as a bonus for using an important disease
Brucellosis can be eradicated from a herd. It only requires
TIME, EFFORT, an UNDERSTANDING of the DISEASE, and COOPERATION;
cooperation between the herd owner, the practicing veterinarian,
and the regulatory agencies.
This publication was produced at a cost of $592.50, or 24.0 cents per copy, to inform cattle producers how
to eliminate brucellosis from their beef herds and techniques in veterinary medicine. 4-2.5M-90
COOPERATIVE EXTENSION SERVICE, UNIVERSITY OF FLORIDA, INSTITUTE OF FOOD AND AGRICULTURAL SCIENCES, John T.
Woeste, director, in cooperation with the United States Department of Agriculture, publishes this information to further the purpose of the
May 8 and June 30, 1914 Acts of Congress; and is authorized to provide research, educational information and other services only to
individuals and institutions that function without regard to race, color, sex, age, handicap or national origin. Single copies of extension
publications (excluding 4-H and youth publications) are available free to Florida residents from county extension offices. Information on bulk
rates or copies for out-of-state purchasers is available from C.M. Hinton, Publications Distribution Center, IFAS Building 664, University of
Florida, Gainesville, Florida 32611. Before publicizing this publication, editors should contact this address to determine availability.