On-farm management systems to control Johne's Disease

Abstract

Johne's Disease is an infectious bacterial disease that primarily affects the intestinal tract of bovine and other ruminant animals. It is caused by a mycobacterium named Mycobacterium avium subspecies paratuberculosis. The microbe is only able to multiply inside an animal's intestinal tract. However, the development of clinical disease does not occur instantly and, in some instances, the organism is known to survive for more than a year in the intestinal tract. The microbe is also resistant to heat, cold and drying and can survive for considerable periods in the envi ronment . The main source of infection is directly from infected animals. Johne's Disease is as much a herd problem in New Zealand as it is a problem for individual animals. There are some recent, but unconfirmed, reports of culturing the microbe, or detecting its genetic components in humans with Crohns disease. Johne's Disease is an animal health problem which affects ruminant animals the world over. It therefore has implications for trade of dairy products as consumers become concerned and informed of animal health issues. It is therefore desirable that livestock industries take a proactive stance in increasing industry awareness and management measures to control the disease. This report gathers available research statistics and findings on the identification and treatment of Johne's Disease (JD) in the New Zealand dairy cow population and makes recommendations on its control through a variety of management systems.