computer simulation model illustrates howJohne's
control takes time and how faster Johne's control can be accomplished by both
changing calf rearing procedures and testing the adult herd to identify and cull
the infectious cows. Of these two basic strategies, changing heifer management
to limit the chance of calves becoming infected (swallowing the organism) is the most important. This web
page will describe in more detail how to implement these two basic techniques
for Johne's disease control in dairy herds.
. . . manure management
number of MAP bacteria excreted by infected cows
are in the feces (manure). Farm sanitation and control over where manure
goes on a farm are critical to control of Johne's disease. Because of
the susceptibility of calves to MAP infection,
it is important to keep them well away from feces of cows that may harbor
the infection. The longer separation of young stock and adults can be
maintained the better. For dairy cattle, the minimum time for complete
separation is the first 6 months of life, the "window" of maximum susceptibility.
Calves should be born in a clean dry environment with minimal fecal contamination. Prompt removal of calves from their dam is recommended not only for control of Johne's disease, but for several other dairy cattle diseases as well. A recent study of 9 dairy herds participating in a Johne’s control program found that the one of the most challenging aspects was maintaining uncontaminated maternity pens. Individual calving pens are optimal, but not feasible for many herds. Instead, designate test-negative and test-positive pens (you could test all your cows at dry-off to have this test information available). At least try to remove calves to an area outside the pen free of adult manure contamination (“the safe zone”) within two hours of birth.
of feed by use of dirty feeding equipment should be avoided. Also, manure
contamination of water supplies, particularly ponds or streams that heifers
can drink from, must be avoided to limit spread of the infection. If you use water troughs, when cleaning them remove the sediment at the bottom and dump it away from where animals might graze – MAP apparently survives for a long time in this substrate.
with MAP is theoretically important as a means
of infection transmission, but is less likely than other modes of transmission
and far more difficult to control. Till contaminated pastures and wait for time and environmental conditions (repeated changes in temperature, minimize shaded soil by cutting grass/crops/shrubs) to kill off MAP on fields. While a majority of the organisms die within three months, a small population can remain for up to a year. Put off stocking contaminated pasture with young animals as long as feasible. Read about survival of MAP in the environment in the "Biology of MAP" section of this site.
infected with MAP will excrete the bacterium
in their milk. This happens most often in cows showing clinical signs
of Johne's disease, but also occurs in infected animals that appear healthy.
Because no diagnostic test can detect all infected animals on a single
herd test, to control Johne's disease it is best if feeding of raw milk,
sometimes called waste milk, and natural nursing can be avoided. Artificial
milk replacers are considered free of MAP because
of the way they are processed. Some sponsors of this website sell milk
replacer products. Please visit the sponsor page to learn more about
A safe and
effective alternative to using milk replacers is to pasteurize waste milk
on the farm. A recent study saw no difference in the number of new cases of Johne’s disease arising in dairy herds between those that pasteurized and those that used milk replacer (Recommended protocols: 145°F (63°C) for 30 minutes for batch pasteurization, or 162°F (72°C) for 15 seconds for flash pasteurization. The milk should be stirred or otherwise in motion to ensure even heat distribution.) Pasteurization kills virtually all MAP that may contaminate raw milk as well as other viral and bacterial agents
that could affect the health of dairy heifer replacements. Some sponsors
of this website sell on-farm
pasteurizers. Please visit the sponsor page to learn more about available
Colostrum, the antibody-rich milk produced by mothers the first few days after giving birth, also can contain MAP. Because colostrum is critical to the health and survival of newborns, feeding of colostrum must be done. Many dairies do not collect and store colostrum sufficiently carefully to minimize contamination. However, the risk of transmitting MAP infections in colostrum can be minimized by following these three simple rules:
of colostrum is technically a fourth alternative. However, the thick viscous
nature of colostrum makes it very difficult to pasteurize and so for practical
reasons it is not advised.
sources of information on calf management in print form can be found in
the "Articles and Brochures" section
of this website. Three articles in particular can help you become a better
MAP infections can be transmitted from mothers to offspring by contact with the mother's infected feces, through infected colostrum or milk from the mother, or across the placenta into the fetus before the calf is born. Depending on the extent to which manure management and milk/colostrum management recommendations listed above can be implemented, there is a moderate to high probability that calves born to MAP-infected mothers will acquire the infection. Consequently, on a case by case basis, it may be wise to cull offspring born to infected mothers. If not culled, it may take two or more years to determine if the young animal became infected, and this will be time lost in pursuit of control or eradication of the MAP in the herd.
The majority of MAP infections in a herd are "invisible". Cows with clinical signs of Johne's disease, diarrhea and weight loss, are only a small fraction of the truly infected animals. The infection has the ability to silently spread from cows to calves long before signs of illness in infected animals are evident. For this reason, laboratory tests are important to determine which cows are infected. Test-positive cows are generally those most likely to be infectious (excreting MAP in milk and manure) and so they should be removed, or at least isolated from, the herd.
to as a test-and-cull program, this practice is essential to successful
control of Johne's disease in herds in a reasonable period of time. Clearly,
there are situations where alternatives must be considered: testing and
culling of all test-positive
animals is not necessarily always required. For instance, some control programs retain cows with low or medium-level ELISA results to generate milk income but these cows clearly tagged and are strictly managed since they are almost certainly shedding MAP on the premises in their manure as well as in their milk. Farmers report that knowing the Johne’s test status of a cow affects when the cow is culled if she develops any other health problems or if her milk production drops. Decisions on how best to implement
testing in a Johne's control program should be made in consultation with
a veterinarian. For details about available laboratory tests for Johne's
disease, see the diagnosis section of this
Sponsors of this website selling diagnostic products for Johne's disease are listed in the Sponsor section of this website.
MAP is resistant to most disinfectants; washable tools, troughs, and feed dishes may be treated as directed on the bottle with a disinfectant labeled as “tuberculocidal”. Since organic material deactivates the disinfectant, items should thoroughly cleaned with soap and water, rinsed and dried before the disinfectant is applied. Tuberculocidal disinfectants usually contain strong chemical compounds and should be used carefully. The instructions provided on the label for proper use and safe handling should be followed precisely.
of this website selling disinfectants
that kill mycobacteria like MAP for Johne's disease
are listed in the Sponsor section of this website.
vaccines exist for Johne's disease; one is made from killed MAP and the other from live, but not capable of causing disease (avirulent) MAP. Only the killed product is available in
the U.S. It is produced by Ft. Dodge Animal Health and sold by Solvay
Animal Health under the trade name Mycopar®. Most published information
concerns the killed vaccine and comments here are restricted to that product.
vaccine is only licensed for use in calves less than 30 days old. It will
decrease the frequency of cows that develop clinical Johne's disease:
diarrhea and weight loss. It will not change the rate that cattle get
infected. Studies in The Netherlands have shown that herd owners who follow
the recommended management changes to control Johne's disease will be
as successful, if not more successful than those who use the vaccine.
unusual circumstances for herds with very high infection rates, the authors
of this website do not recommend use of the vaccine for Johne's disease.
Visit the Articles and Brochures section of this website There you can find several excellent articles that you can download and print. They summarize Johne's disease programs and describe real world stories of how farmers are successfully controlling this disease.