Ice-berg Diseases in Sheep – Ovine Johnes Disease (OJD)
Johnes – Ovine Johnes Disease (OJD) was first described in 1985. OJD is a condition caused by the bacterium “Mycobacterium avium spp. Paratuberculosis” (MAP). Johne’s is a condition which affects all ruminants, although not in the same way. OJD is a chronic condition which is responsible for causing a reduction in productivity, immunity and fertility. Research by the University of Glasgow also indicates that mortality rates are significantly higher (4-12%) within infected flocks in comparison to healthy flocks (1-2%). There is no perfect test to diagnose Johnes in a live animal – however, a licenced vaccine is available in the UK which can reduce both the severity of clinical signs and subsequent mortality rate.
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