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[[Image:Tuberculosis M bovis.jpg|right|thumb|250px|<small><center>Tuberculosis caused by ''M. bovis'' (Image sourced from Bristol Biomed Image Archive with permission)</center></small>]]
[[Image:Tuberculosis M bovis.jpg|right|thumb|100px|<small><center>Tuberculosis caused by ''M. bovis'' (Image sourced from Bristol Biomed Image Archive with permission)</center></small>]]
==Description==
==Description==
'''Tuberculosis''' in cattle is caused by ''[[Mycobacterium bovis]]''. It is a chronic disease characterised by nodular lesions in any organ, although the respiratory system is most commonly affected. The nodules often become nectroic with a caseous centre. rupture of the nodules releases ...
'''Tuberculosis''' in cattle is caused by ''[[Mycobacterium bovis]]''. It is a chronic disease characterised by nodular lesions in any organ, although the respiratory system is most commonly affected. The nodules often become nectroic with a caseous centre. The primary lesions may disseminate to involve other body systems.
A higher level of infection is required to establish the alimentary form of the disease and this is reflected by its lower incidence in comparison to the respiratory form.
Inhalation of ruminal gases is the most common route of entry for the mycobacterium organism, and spread of the disease is usually via cow to cow contant. Cattle can also become infected by ingestion of the causative agent, this is thought to be the route of entry when the badger is involved, infecting grazing land or water troughs.
Inhalation of ruminal gases is the most common route of entry for the mycobacterium organism, and spread of the disease is usually via cow to cow contant. Cattle can also become infected by ingestion of the causative agent, this is thought to be the route of entry when the badger is involved, by infecting grazing land or water troughs. Calves with infected dams can become affected via the milk, and intrauterine infection at coitus has been reported.
Historically bovine TB was a major cuase of human TB, but the introduction of tuberculin testing and slaughter, meat inspection at abatoirs, the pasturisation of milk and the BCG vaccination has dramatically reduced transmission to humans and bovine TB as a cuase of human disease is now very low indeed.
Historically bovine TB was a major cuase of human TB, but the introduction of tuberculin testing and slaughter, meat inspection at abatoirs, the pasturisation of milk and the BCG vaccination has dramatically reduced transmission to humans and bovine TB as a cuase of human disease is now very low indeed.
==Diagnosis==
==Diagnosis==
The intradermal tuberculin test
The intradermal tuberculin test
===Clinical Signs===
===Clinical Signs===