Control is easy, it just takes time. PREVENTION | ELIMINATION Johne's disease can be controlled and even eliminated from infected herds, however, it takes athorough understanding of thedisease by animal owners, consultation with a veterinarian, and requires use of one or more of the available diagnostic tests. Half-hearted attempts to control Johne's disease will generally fail. Control of Johne's disease also takes time. A typical herd clean up program may take 5 years or longer.Faster clean up programs are possible, but they are usually more expensive. The basics of control are simple: new infections must be prevented, and animals with the infection must be identified and removed from the herd.

There are two basic strategies for control of Johne's disease: #1 stop new infections from occurring in calves, and #2 eliminate the source of infection, infected adult cattle in the herd. Doing both strategies will effective control, or possibly eliminate, Johne's disease from a dairy cattle herd.

A computer simulation model illustrates how Johne'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 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

The largest number of M. paratuberculosis 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 M. paratuberculosis 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 mother is recommended for control of Johne's disease, as well as several other dairy cattle diseases.

Manure contamination 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.

Pasture contamination with M. paratuberculosis is theoretically important as a means of infection transmission, but is less likely than other modes of transmission and far more difficult to control. If possible, infected pastures should be tilled, otherwise waiting for environmental conditions to cause destruction of M. paratuberculosis on pastures must be depended on. This can take up to a year. Read about survival of M. paratuberculosis in the environment in the "Biology of M. paratuberculosis" section of this site.

. . . milk management

Many animals infected with M. paratuberculosis 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 M. paratuberculosis 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 available products.

A safe and effective alternative to using milk replacers is to pasteurize waste milk on the farm. Pasteurization kills virtually all M. paratuberculosis 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 products.

Colostrum, the antibody-rich milk produced by mothers the first few days after giving birth, also can contain M. paratuberculosis. Because colostrum is critical to the health and survival of newborns, feeding of colostrum must be done. However, the risk of transmitting M. paratuberculosis infections in colostrum can be minimized by following these three simple rules:

Pasteurization 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.

Excellent 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 calf raiser:

• "Raising Calves - The 5Cs of a Healthy Start"
• "Immunology of the Calf"
• "Answers to Pasteurization Questions"
  

. . . culling offspring of infected mothers

M. paratuberculosis 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 M. paratuberculosis-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 M. paratuberculosis in the herd.

Test-and-cull program

The majority of M. paratuberculosis 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 M. paratuberculosis in milk and manure) and so they should be removed, or at least isolated from, the herd.

Referred 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. 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 web site.

Sponsors of this website selling diagnostic products for Johne's disease are listed in the Sponsor section of this website.

Disinfection

M. paratuberculosis is resistant to most commonly used disinfectants. Destruction of M. paratuberculosis on surfaces that might be contaminated requires thorough cleaning with soap and water followed by application of a disinfectant that is "tuberculocidal". Tuberculocidal disinfectants usually contain strong chemical compounds and should be used carefully. Label instructions for proper use and safe handling should be followed precisely.

Sponsors of this website selling disinfectants that kill mycobacteria like M. paratuberculosis for Johne's disease are listed in the Sponsor section of this website.


Vaccination

Whether vaccination has a place in Johne's disease control programs is controversial. Two vaccines exist for Johne's disease; one is made from killed M. paratuberculosis and the other from live, but not capable of causing disease (avirulent) M. paratuberculosis. 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.

The U.S. 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.

Except under 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.

Articles on Johne's control

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.