Tend-R-Leen: The original no-roughage feeding program

On July 12, 2005, the Minnesota Board of Animal Health in conjunction with the United States Department of Agriculture (USDA) announced the confirmation of a tuberculosis infected beef cattle herd in Roseau County . This is the first positive herd identified in Minnesota since 1971, when the state was declared free from tuberculosis.

The Minnesota Board of Animal Health is working closely with the USDA to quickly and effectively eliminate tuberculosis infected cattle in Minnesota to ensure that Minnesota retains its tuberculosis free status.

Bovine tuberculosis is a contagious, infectious, and communicable disease affecting cattle, bison, deer, elk, and humans. In both animals and people, the disease can cause lesions of the lung and bone, weight loss, and general debilitation. Bovine tuberculosis can be fatal.

What is bovine tuberculosis?

Bovine tuberculosis (TB) is an infectious disease that is caused by the bacteria Mycobacterium bovis. Bovine TB primarily affects cattle, however, other animals may become infected.
Tuberculosis in humans and other mammals is usually caused by Mycobacterium tuberculosis or Mycobacterium bovis. While M. tuberculosis is the single greatest cause of infectious disease in humans worldwide, M. bovis affects the largest number of animals throughout the world. M. bovis causes a disease which can be transmitted between wildlife populations and animals raised as a food source (farm animals). In humans, tuberculosis occurs most often in the lungs. Disease due to M. bovis (also known as bovine tuberculosis) in animals may occur in the lungs but may also occur in the intestines and other parts of the body.

How was bovine tuberculosis detected in Minnesota ?
A five-year-old cow was detected at slaughter to have lesions consistent with tuberculosis. The animal was traced to a beef herd in Roseau County . This launched an investigation, which confirmed the presence of bovine tuberculosis in this herd. After a

whole herd test, 21 additional cattle out of the 568 adult cattle tested in the herd were identified as suspect for tuberculosis and were tested.

What is the Board of Animal Health doing to control this situation?
The Minnesota Board of Animal Health (BAH) is working closely with the U.S. Department of Agriculture (USDA) to eliminate tuberculosis infected cattle in Minnesota . The infected herd in Roseau County is quarantined and awaiting depopulation. The BAH has identified additional herds which purchased or sold cattle from the infected herd. The animals bought or sold from the infected herd will be purchased by the USDA, euthanized and tested for tuberculosis. If these animals are negative for tuberculosis, the herds they currently reside in will be tested for tuberculosis using a screening test. In addition, a few herds have fence-line contact with the infected herd and might have been exposed to tuberculosis due to their pasture grounds being close together. These herds were also placed under quarantine and will be tested for tuberculosis. With any of the currently quarantined herds, if they test negative, they will be removed from quarantine. If positive, they will be depopulated.

Will this affect Minnesota ’s tuberculosis free status?
The identification of one infected herd does not automatically warrant removal of Minnesota ’s tuberculosis free status. Removal of free status will occur only if another herd is independently identified as infected with tuberculosis within the next 48 months or if the BAH does not comply with federal timelines for depopulation of the infected herd. The BAH is working to ensure that the later does not occur. The other herds currently under quarantine will not, if positive, be considered independent infections as they are linked to the initial infected herd by animal movement between the herds.

What is my state’s Tuberculosis status?

The USDA has established five status levels, or stages, for states and zones as they make progress eradicating bovine tuberculosis. There

are five stages which are generally based upon the prevalence of bovine tuberculosis within cattle. The five stages are: Non-accredited, Accredited Preparatory, Modified Accredited, Modified Accredited Advanced, and Accredited-free. Currently, we have 49 States and Territories which are Accreidted-Free. Three States currently have either total or partial Modified Accredited or Modified Accredited Advanced Status. A current listing of State Eradication Status levels for Bovine Tuberculosis as well as for other USDA disease eradication programs is available on the Veterinary Services website. You can access that information by visiting this link: http://www.aphis.usda.gov/vs/nahps/domestic-animal.html

How common is bovine tuberculosis?
The USDA has conducted an aggressive bovine tuberculosis eradication program since 1917. This program has been very successful, and the country is largely free of the disease. Minnesota , prior to the identification of the infected beef herd in Roseau County , has been free of bovine tuberculosis since 1971. Ongoing problems exist in Michigan (associated with deer) and Texas (associated with Mexican cattle infections). These are localized problems and do not affect the majority of cattle in these states.

What are the signs of bovine tuberculosis?
Bovine tuberculosis is a progressive, chronic disease. It can take months to years from infection to the development of clinical signs of the disease. Infected animals will become gradually thinner, less active, and depressed. As infection usually involves the lungs, infected animals may have difficulty breathing, cough, or show nasal discharge. At slaughter, classic signs of bovine tuberculosis are abscesses filled with a gritty white or yellow substance in the lungs or lymph nodes.

How is bovine tuberculosis transmitted?
Bovine tuberculosis primarily affects the respiratory tract but can also spread to other parts of the body. The primary route of transmission is the exchange of respiratory secretions between infected and uninfected animals. This can be achieved through nose-to-nose contact or by the inhalation of aerosol droplets that have been exhaled by an infected animal. Animals may also become infected with M. bovis by ingesting the bacteria. This could occur by ingesting feeds that have been contaminated with M. bovis by other infected animals. Carnivores may become infected with bovine TB by eating infected carcasses.

What should I do if I suspect bovine tuberculosis?
Though bovine tuberculosis is now very rare and clinical signs are common with many other diseases, if you suspect tuberculosis contact your herd veterinarian. They will evaluate your cattle and contact your state’s Board of Animal Health if appropriate.

Any herd containing an animal classified as a suspect or reactor to any of the tests for bovine tuberculosis shall be quarantined until further testing rules out Mycobacterium bovis. A herd consists of all animals that are part of the USDA Bovine Tuberculosis Eradication Program and include cattle, goats, bison and captive cervidae. Animals under quarantine are not permitted to leave their premises, and no animals may enter the premises, unless a state or federal permit has been obtained.

Do deer in the affected area pose a risk to livestock?
Though deer in Michigan do serve as a reservoir of bovine tuberculosis, this does not appear to be the case in Minnesota for several reasons. The M. bovis strain isolated from the infected Minnesota herd does not match that found in Michigan . Minnesota has no history of tuberculosis infection in deer or other wildlife. There are fewer deer in the area of the infected herd (15-20/square mile) than in the affected part of Michigan (50/square mile). In order to ensure that deer do not harbor the disease, the Minnesota Department of Natural Resources has plans to test deer in the area of the infected herd during the upcoming hunting season.

Can bovine tuberculosis infect people?
Tuberculosis is a disease primarily affecting the respiratory system. Most human tuberculosis is caused by the bacteria Mycobacterium tuberculosis, which is spread from person to person and rarely infects animals. Bovine tuberculosis is caused by the closely related bacteria Mycobacterium bovis, which is capable of infecting all mammals including people. The United States has actively pursued a bovine tuberculosis eradication program since 1917. This program, together with food safety initiatives, has been very effective in reducing the likelihood of people contracting tuberculosis from M. bovis.