Most common in weaned calves. It occurs most commonly when they go onto lush pasture and gut bacteria change and produce thiaminase enzymes that destroy B1 in the rumen. It can sometimes happen on brassicas crops high in sulphates.

Signs start mild and progress. Calves separate and stop eating. They become blind and disorientated. Head pressing and shaking. Stiff legs, convulsion and death.

Other possibilities: Ryegrass staggers Listeria Pulpy kidney

Treatment is the best diagnosis as lab diagnosis takes too long.

Treat calves twice daily for 3 days. 1 ml per 10 kg Lwt Ideally the first injection is slowly I/V followed by intra muscular injections.

Less severely affected calves will respond in 12 - 24 hours.