Johne's disease
Johne's disease is an infectious disease of cattle caused by infection with a bacteria called Mycobacterium Avium subspecies Paratuberculosis (MAP). Because of the long incubation period, most infected animals show clinical signs as adults, with weight loss and scour causing debility and eventually death. The major economic losses are caused by the subclinical effects including poor production, infertility and premature culling.
Severe diarrhoea in a cow with Johne's disease ©Peter Jackson