Johne’s Disease

Johne's disease (pronounced "yo-knees") is a contagious, chronic, and usually fatal infection that affects

primarily the small intestine of ruminants. All ruminants are susceptible to Johne's disease. Johne's

disease is caused by Mycobacterium paratuberculosis, a hardy bacteria related to the agents of leprosy

and tuberculosis. The disease is worldwide in distribution.

Clinical Signs

Signs of Johne's disease include weight loss and

diarrhea (in cattle) with a normal appetite. Several

weeks after the onset of diarrhea, a soft swelling may

occur under the jaw (bottle jaw). Bottle jaw or intermandibular edema is due to protein loss from the

bloodstream into the digestive tract. Animals at this

stage of the disease will not live very long, perhaps a

few weeks at most.

Signs are rarely evident until 2 or more years

after the initial infection (in cattle, maybe sooner in

other species), which usually occurs shortly after

birth. Animals are most susceptible to the infection in

the first year of life. Newborns most often become

infected by swallowing small amounts of infected

manure from the birthing environment or udder of the

mother. In addition, newborns may become infected

while in the uterus or by swallowing bacteria passed

in milk and colostrum. Animals exposed at an older

age, or exposed to a very small dose of bacteria at a

young age, are not likely to develop clinical disease

until they are much older than 2 years.

A national study of U.S. dairies, Dairy NAHMS

96, found that approximately 22 percent of U.S. dairy

farms have at least 10 percent of the herd infected

with Johne's disease. The study showed that for

herds with a percentage of cull cows with clinical

signs less than 10 percent, the annual cost of

Johne’s disease is $40 per cow. Infected herds that

had more than 10 percent of their cull cows showing

clinical signs showed losses of $227 per cow in their

inventory per year. This loss was due to reduced

milk production, early culling, and poor conditioning

at culling. Accurate estimates of the cost of Johne's

disease in beef herds still need to be determined.

Farm–specific plans can be implemented to

reduce economic losses and cleanup Johne's disease from the farm. For more information on Johne's

disease, diagnosis, prevention, and control, contact

your herd veterinarian or your State's extension

office.

How Johne’s Disease Spreads 

The primary site targeted by Johne's disease is

the lower part of the intestine know as the ileum. The

bacteria that causes Johne’s disease embeds itself in

the wall of the ileum. As an immune response, infected tissues attempt to regenerate healthy tissue,

which leads to visible thickening of the intestines.

This prevents nutrient absorption and weight loss

results. Late in the infection, antibody production by

the animal can be found in serum of animals and is

an indicator that clinical signs of disease and death

from the infection will soon follow.

Prevention

Transmission of Johne's disease occurs when

healthy–looking but infected animals are introduced

to the herd. Owners of herds that are not infected

should take precautions against introduction of

Johne's disease. Such precautions include keeping a

closed herd, or requiring replacement animals come

from test–negative herds.

In April 2002, the U.S. Department of

Agriculture’s Animal and Plant Health Inspection

Service (APHIS) Veterinary Services published

Uniform Program Standards for the Voluntary Bovine

Johne’s Disease Control Program (VBJDCP). The

objective of this program is to bring uniformity to the

States that currently have individual Johne’s disease

control programs in place and to assist those States

that would like to implement programs of their own.

Some basic prevention strategies are:

• Calves, lambs, kids, and other ruminants should 

be born in a clean environment.

• Reduce newborns’ exposure to manure from 

adult animals by separation when possible.

• Avoid manure contamination of feed by using 

feed bunks and not using the same equipment to 

handle feed and move manure.

• Avoid manure contamination of water sources 

where animals drink.

• For natural colostrum needs of newborn animals,

use colostrum from Johne's–negative animals.

• Do not pool colostrum.

• Avoid natural nursing and milk feeding whenever 

possible. Feed an artificial milk replacer or 

pasteurized milk instead of raw milk to supply the

needs of newborns. Never feed pooled milk or 

waste milk.

• Thoroughly clean the udder and teats before 

collection of the colostrum to avoid manure 

contamination.

Factsheet

Veterinary Services March 2003

APHIS
• M. paratuberculosis can survive up to a year in 

the environment so if possible, for pastures that 

have become contaminated, till the ground or 

graze using nonreplacement feeder cattle.

• Identify all females in the herd. Identify and 

remove, or keep separate, all test–positive 

animals.

• Prevent infection from spreading by culling or 

separating offspring of infected mothers as soon 

as possible.

• If purchasing herd additions, try to buy from low 

risk herds. Some herds are enrolled in the 

VBJDCP to help identify their herd as low risk.

• Work with your veterinarian to develop a strategic 

plan for Johne's prevention and control for your 

farm. Consult with a veterinarian about which 

Johne's test is best for your situation and use a 

test–certified diagnostic laboratory.

APHIS’ Role

APHIS’ role in the design and implementation of a

national Johne's disease control program has been to

provide expertise and help coordinate implementation

of Johne's disease programs by the States. In addition, APHIS works closely with State and industry

counterparts through the U.S. Animal Health

Association’s (USAHA) national Johne’s disease

working group.

In the fall of 1995, USAHA appointed the working

group to assist the Johne's committee of USAHA in

developing a national, coordinated Johne's disease

effort in conjunction with the States and cattle industries. The working group, in coordination with APHIS,

developed a strategic plan designed to reduce the

prevalence of Johne's disease in U.S. cattle. This

plan includes a national educational campaign, the

VBJDCP, and guidelines for States to assist infected

herds. This national program is designed to be producer driven and voluntary. Other U.S. livestock

industries are examining potential certification and

control programs for their industries as well. The

American Zoological Association has prepared

Johne's disease guidelines.

For More Information

For more information on the working group’s activities, visit USAHA's Web site at: http://www.usaha.org.

For more information on APHIS’ role in developing

and implementing the VJDBCP contact:

Dr. Michael Carter

APHIS-VS

Center for Animal Health Programs

4700 River Road

Riverdale, MD 20737

Phone: (30l) 734-4194

or visit the APHIS Web site at www.aphis.usda.gov.

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United States Department of Agriculture • Animal and Plant Health Inspection Service • Safeguarding American Agriculture