A2S-LancMt«r Fanning, Saturday, April 1,1989
(Continued from Pago A 1)
farmers with a source of unin
fected animals with which to
replace culled cows and, according
to Yoxheimer, encourage security
measures to prevent the spread of
the disease.
The program, which is currently
making the bureaucratic rounds,
will be voluntary. In order to be in
the program, farmers would need
to meet several requirements
including working with an accred
If you have one positive cow with clinical signs ,
you probably have 6 to 12 that will test positive on
the fecal culture and IS to 25 others that are
infected but can’t be proved positive.
ited veterinarian, having three con
secutive negative fecal tests for the
herd with the tests being 12 to 14
months apart, purchasing replace
ments from a negative herd, and
refraining from using a Johnc’s
Disease vaccine.
According to Yoxheimer, when
the program is implemented, test
ing facilities would be expanded
by allowing Penn State and the
University of Pennsylvania to test
fecal cultures.
Preventative measures
Because there is no known cure
or treatment for Johne’s, experts
only can instruct farmers and vet
erinarians how to control and
eradicate it through management
practices.
Recent studies have proven that
the group most susceptible to the
Johne’s bacteria, mycobacterium
paratuberculosis, are newborn and
young calves. “The resistance to
infection increases with age,”
reported Dr. Raymond W. Sween
ey of New Bolton Center. "Most
calves are probably infected short
ly after birth, especially if they are
permitted to suckle an udder that is
contaminated with manure from an
infected adult cow.”
Management of the disease
begins before a cow freshens. She
should be put in a pen used only for
calving, and the pen should be as
clean as possible, which usually
will mean cleaning out old bedding
and manure and spreading new
bedding.
Farmers should try to be present
at calving to clean udders if the calf
will be allowed to suckle, which is
an acceptable practice for known
negative dams. If the dam is
Johne’s positive, the calf should be
separated from the cow as soon as
possible, before suckling. Colo
strum should be fed from a bottle,
according to Dr. Glen F. Hoffsis,
professor of veterinary medicine at
Ohio State University. “Obtain
colostrum from a test negative cow
or pasteurize colostrum from a
positive cow,” he said. "Pasteuriz
ing colostrum is more difficult
than milk; it turns to a pudding
consistency, especially if the
temperature (during pasteuriza
tion) gets very hot.”
Transmission
Johne’s is shed in the manure of
positive cows, and transmission
usually occurs when the manure is
ingested. “It is possible, however,
for the Johne’s organism to pass
through the placenta,” stated
Sweeney. “While up to 25 percent
of pregnant, Johnc’s-positivs bows
had infected offspring in one
study, the likelihood of transmis
sion probably depends on the stage
of the dam’s infection. If the infec
tion has progressed to .the point
that the cow has clinical signs,
there is a much greater chance that
the calf will be bom with the
Management Practices Can Help
infection.”
There are indications that the
Johne’s organism can be found in
the milk of infected cows. But as
with in-utero transmission, this
occurs most frequently in cows
showing clinical signs of the dis
ease. It is a good idea not to feed
this milk or colostrum, to calves.
. Calves shodl(l be libused sepa
rately from adults so that ingestion
of infected mannreis aotpossible.
The housing sfiotiid he dphill and
at least four feet away so that barn
yard run-off will not reach the
calves. Don’t park manure hand
ling equipment near the hutches or
pens, Hoffsis warned. He cited an
example where the former parked
his spreader between two rows of
hutches, and when it rained, man
ure from the spreader ran out and
into the hutches where calves
could drink it
Young stock should be kept
separate from adults until they are
at least 12 months old, longer if
possible. As they grow older the
less likely they will become
infected.
“Cattle over two years of age are
not readily infected even when
introduced to a contaminated envi
ronment,” said Dr. Robert Whit
lock of New Bolton Center. “Thus,
with each additional month of age
the animal becomes more resistant
to infection. However, large num-
There is no known cure or treatment for Johne’s
Disease , but it can be controlled and eradicated
through management practices.
bers of infecting organisms will
overcome the age resistance.”
Manure should be handled dif
ferently as well, according to Hof
fsis. “All manure must be spread
on fields intended for cultivation
and never on pastures,” he stated.
“Field crops don’t suck up the
(Johne’s) organisms. The only
way it might get into the feed is if it
is particularly dusty on the day you
harvest"
Calves shouldn’t be pastured,
but if they must be, it should be on
a field that hasn’t been spread with
manure or been grazed on by
adults. Rivers and streams, or other
moving bodies of water, aren’t
generally a concern for adult cows.
“The Johne’s organism can live
three to five months in a stream,
but this isn’t a probable method of
infection because the organism is
greatly diluted and older cows are
more resistant,” said Sweeney.
Standing water, however, is a
great concern, according to Hof
fsis. “If the water is not moving,
the dose load (of the organisms)
could get high,” he warned. The
level could get high enough to
infect adult cows.
Waterers should not be shared
between adults and young stock as
adults will sometimes defecate in
the water. For the same reason,
bunk sweepings shouldn’t be fed
to young stock.
First diagnosed in the United
States in 1908, Johne’s is difficult
to detect and none of the diagnostic
tests are 100 percent accurate. Part
Spotting Johne’s
of what makes detection difficult is
the slow incubation period, which
is two or more years. In addition,
there aren’t any clinical signs of
the disease during the early stages
of infectioa Clinical signs are
often brought on by the stress of
calving. Sometimes, however,
cows never develop clinical signs,
a response that is based partially on
the age of the cow at the time of
infection and the dose of the
organism.
Clinical signs include weighti
loss to the point of emaciation yet a *
healthy appetite, a decrease in milk
production, a predisposition to
mastitis and fertility problems,
diarrhea, and edema, a large, soft
swelling, under the jaw.
If a farmer finds one animal with
clinical signs, he’s probably only
reached 'the tip of the iceberg,
according to Whitlock. “If you
have one positive cow with clinical
ar*
attle over two years of age are not readily
infected even when introduced to a contaminated
environment ” Dr. Robert Whitlock.
signs, you probably have six to 12
that will test positive on the fecal
culture and 15 to 25 others that are
infected but can’t be proved
positive."
He estimates that one out of five
cows in Pennsylvania has Johne’s.
Currently the most reliable
method of detecting infected ani
mals is the fecal culture, according
to Dr. Arian Zarkowgr of Penn
State. 'The main advantage of this
testis that it has almost ICO percent
specificity when performed in
most bacteriology labs," he said.
Among the disadvantages are low
sensitivity, the need for multiple
testing, a long incubation period,
and possible contamination of the
sample. Studies have found that
this test will become more sensi
tive if it is centrifuged before cul
turing. Centrifiguation can
increase the likelihood of contami
nation, however.
Other tests that have been used,
with varying degrees of specificity
and sensitivity include tissue cul
ture test of certain organs,
Enzyme-Linked Immunosorbent
Assay (ELISA), Dot Immunobind
ing Assay, and Agar Gel Immuno
diffusion Assay.
“There are two newer tests
under development that may pro
vide certain advantages in the
diagnosis of Johne’s,” reported
Zarkower. One is the radiometric
detection of M. paratuberculosis.
A relatively new culture proce
dure, this test incubates the fecal
material in a solution containing a
special acid. If the Johne’s organ
ism is present, it uses the acid and
releases a substance that can be
measured.
“This test is potentially as spe
cific as the currently used culture
method,” said Zarkower. “But it
requires only about 10 days of
incubation time. The test is cur
rently being evaluated and is not
being widely used in part because
of the highly sophisticated equip
ment required.”
The other new test is a nucleic
acid gene probe. It is based on the
ability to identify nucleic acid
You Beat Johne’s
sequences that are unique to the
Johne’s organism. There is not
enough information at this time to
determine how useful it will be in
diagnosing Johne’s.
Steps to take
If Johne’s is found in the herd,
the tint step for a farmer is to
assess the magnitude of the prob
lem, according to Hoffsis. He
should try and find out the origin of
the infected catde. “Many times a
farmer can trace all his problems to
when he purchased a certain cow,”
Hoffsis commented.
The next step is to determine the
number of cases within the herd.
“When it is first diagnosed, fecal
test your whole herd.” he advised.
“If there is only one case, don’t
panic but take actions to prevent
mote cases. Too many people who
don’t pay attention to the disease
tight away find it builds in the
herd.”
Most experts recommend isolat
ing cows with diarrhea or cows
that look emaciated. “But where
do you isolate cows on a dairy
farm?" Hoffsis asked. In one case
that he cited, the fanner was con
cerned about spreading the disease
to other adults, and so penned the
positive animal with the young
stock.
Isolating cows that exhibit clini
cal signs from other adults is not as
important as keeping them away
from young stock. If possible all
positive cows should be culled
right away. In Pennsylvania,
which is one of the only states with
an official Johne’s program, farm
ers can receive indemnity for
culled cows if they are in the stale
program.
Culling is hard for farmers parti
cularly if the animal doesn’t exhi
bit clinical signs. “It’s difficult for
farmers to get rid of two-year-olds,
especially when they’re producing
a lot of milk," said Hoffsis. “I tell
them to milk the cow through most
of the lactation before culling her.”
Sweeney recommended that,
despite the cost, dairymen should
Most cqlves are infected shortly after birth,
especially if they suckle a manure coated udder.
Puterbaugh Named
To Herdsman Position
TUNKHANNOCK (Wyoming)
Lester Puterfoaugh has recently
been appointed herdsman for Sire
Power’s headquarter facilities in
Tunkhannock, Pennsylvania.' In
making the announcement, Assis
tant Manager J. Lloyd Ebersole
stated that Puterbaugh will be
responsible for supervising daily
barn operations at the main facili
ty which houses the proven sire
lineup and young sires entering
sampling, as well as the separate
mini-stud facility. These response
bilities include feeding and care of
the bulls, monitoring sire health,
and overseeing semen collection
procedures.
Puterfoaugh has been with Sire
Power’s bam crew since he joined
the organization in December
1979. He had previously been
employed with Louden Hill
Farms. In his spare time, Puter
baugh enjoys hunting, fishing, and
consider culling all offspring from
Johne’s-positive cows, especially
those from heavily infected cows.
Although if the positive cow is
from valuable bloodlines, the far
mer could save her genes by flush
ing her embryos.
While trying to eliminate
Johne’s from the herd, farmers are
recommended to retest the herd
annually until one or two negative
tests are obtained. Replacements
should come from known-negative
herds.
A Johne’s vaccine is available,
however, it is not 100 percent
“The vaccine is effective in reduc
ing the incidence or delaying the
onset of clinical signs,” said Hof
fsis. “But some vaccinated animals
may have a subclinical infection
and shed organisms.”
The vaccine must be given to a
calf one month or younger in age
as an injection in the brisket. In
most states it can only be used in
positive herds as it causes some
problems to regulators with con
fusing test results. It must be admi
nistered in Tuberculosis-free herds
by an approved veterinarian. In
addition, some states have not
approved its use.
There some side effects to using
the vaccine. It can cause lumps to
form at the site of the injection that
vary from 1 to several inches in
diameter. It may be positive on
later Johne’s serologic or sensitivi
ty tests, and its use may cause reg
ulatory problems with preparation
and approval of health certificates.
“Don’t use it as a replacement
for management practices,” cau
tioned Hoffsis. “If you have a
choice, employ management prac
tices first.”
Johne’s Disease is a confusing
disease that costs American dairy
fanners more than $lO5 million
yearly, $6 million of that in Pen
nsylvania alone. Researchers are
attempting to learn cures and treat
ments, but until they find these,
good management practices are
die answer to eliminating Johne’s.
The last part of this series will
run next week and will discuss the
research being done by Penn State
and the University of
Pennsylvania.
camping. Puterbaugh and his fam
ily have relocated to the herds
man’s house at Sire Power