Johne’s Disease in Goats Q:
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do goats with clinical signs (CLA) of Johne’s disease Lymphadenitis and Caprine Arthritis-Encephalitis Virus Johne’s (“YO-knees”) disease is a Why fatal gastrointestinal lose weight and become weak? (CAEV)—laboratory tests are needed to confirm a diagnosis. disease of goats and other ruminants (including cattle, When an animal with signs of Johne’s disease is discovsheep, elk, deer, and bison) that is caused by the bacterium When an animal is infected with the bacteria reside in ered, itMAP, is very likely that other infected animals—even those Mycobacterium avium subspecies paratuberculosis (MAP). the last part of the small intestine—the ileum—and the intestinal lymph that still appear healthy— are in the herd. Control of the Also known as paratuberculosis, this infection is contagious, nodes. At some point, the infection progresses as bacteria multiply and infection that yousystem and your veterinarian address it in which means it can spread intake yourover herd.more and more of the tissue. Therequires goat’s immune the whole herd and not just on an individual The MAP organism is most commonly passed in the maresponds to the bacteria with inflammation that thickens the intestinal animal basis. nure of infected animals. Thewall infection usually spreads and prevents it from from absorbing nutrients. As a result, a goat in the ill stage of Johne’s disease in effect toinfected death. At thisMAP, the bacteria reside When anstarves animal is with adult goats to kids and occursclinically when a young animal swallows stage the organism may also spread beyond the gastrointestinal tract, in the last part of the small intestine—the ileum—and the the organism via water, milk or feed that has been contamtravelling in the blood to muscles or other major organs such as the liver intestinal lymph nodes. At some point, the infection proinated by manure from infected animals. Most owners are or lungs. gresses as bacteria multiply and take over more and more of taken by surprise when the infection is diagnosed, and learn the tissue. The goat’s too late that the infection has immune system retaken hold in multiple animals sponds to the bacteria in a herd. with inflammation that Due to lack of testing and thickens the intestinal reporting, it is not known how wall and prevents it widespread Johne’s disease is from absorbing nutriin goats in the United States. ents. As a result, a goat The infection has been conin the clinically ill stage firmed, however, in many goat of Johne’s disease herds throughout the counin effect starves to try—in milk, meat, heritage death. At this stage and other breeds—and it the organism may also is a problem in most other spread beyond the goat-rearing countries as well. gastrointestinal tract, The costs of this infection Top: Thickened intestinal mucosa caused by Johne’s disease. travelling in the blood range from economic losses— Bottom: Thin, pliable, normal intestine to muscles or other due to reduced production and major organs such as increased culling for meat and the liver or lungs. milk animals—to emotional losses—for those whose goats Since there is no cure for Johne’s disease, control of the are more pets than agricultural investments. infection is critical. Control of Johne’s disease takes time and There is no cure for Johne’s disease, and there is not a strong commitment to management practices focused on anapproved vaccine for goats in the United States to help protect them rom infection. Therefore, prevention is the key keeping young animals away from contaminated manure, milk, feed and water. A typical herd clean-up program may to control. take a number of years. The basics of control are simple: new A goat that appears perfectly healthy can be infected infections must be prevented, and animals with the infection with MAP. Although goats become infected in the first must be identified and removed from the herd. few months of life, many remain free of clinical illness until Your State Designated Johne’s Coordinator can help you months or years later. When goats finally do become ill, the undertake an on-farm risk assessment that evaluates your symptoms are vague and similar to other ailments: rapid operation, your resources and your goals. weight loss and, in some cases, diarrhea. Despite continuing The University of Wisconsin School of Veterinary Medto eat well, infected goat soon become emaciated and weak. icine’s Johne’s disease website—www.johnes.org—adSince the signs of Johne’s disease are similar to those for dresses all aspects of Johne’s disease for multiple species, several other diseases— parasitism, dental disease, Caseous
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8 - The Boer Goat
