Figure 1. Johne's disease is an important differential for low body condition score and poor performance that should be routinely investigated. Antibody serology tests have very low sensitivity compared with faecal polymerase chain reaction (PCR).

Ovine Johne's disease

The two main groups of MAP strains are ‘type S’ and ‘type C’, named after the host species from which they were originally isolated, sheep and cattle respectively (Collins et al, 1990). This...