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Scabby mouth

Scabby mouth is a viral infection that causes painful lesions in affected animals. Infection occurs through breaks in the skin and can occur anywhere on the body. 

Areas commonly affected are the mouth, feet, udders, and the poll of rams. Thistles and fibrous feed often predispose animals to the mouth lesions. The infection is self-curing and lasts about 4 weeks. During the disease course, a lamb’s feeding is restricted, causing significant impacts on weight gain and some may even die. The production impacts of the disease multiplied across all the lambs that are infected add up rapidly. Older ewes can still get scabby mouth, but the severe disease tends to be more prevalent in younger animals because of their weaker immune status.

Vaccinating is an effective means for disease control. However, it is important to note that farms that are free of the disease should not vaccinate as they will introduce the disease onto their farm by vaccinating. Tailing is a practical time in the calendar year to vaccinate lambs. A single dose of vaccine is usually enough, as this provides good primary immunity.

The vaccine should be stored the fridge until it is used and only the amount needed for the day should be taken to the yards. During use keep it in a chilly bag and out of direct sunlight. The vaccine is given on the inside of the back leg unless fly treatments are being used, in which case the inside of the back leg should be used. Seven to 10 days post vaccination 20 lambs should be checked to see if the vaccine has ‘taken’. A successful vaccination (a ‘take’) appears as a raised whitish line surrounded by an area of inflammation. This is critical to assess vaccine uptake as vaccine failure can occur.

A note on safety: scabby mouth is a zoonoses, meaning the disease is transferable to people. Farmers and shearers should take caution as they are most at risk of the disease due to their close contact with infected animals. Young children and immunocompromised people should not have contact with infected animals.

Please talk to your vet if you are having problems with scabby mouth and are wanting to start a vaccination program.