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Vitamin B1 deficiency in calves

Vitamin B1 (thiamine) is a vitamin that is produced by bacteria in the rumen of cattle.

Cattle have a daily requirement for thiamine and the bacteria will normally produce enough to meet this. Like most B vitamins thiamine is not stored by the body.

Vitamin B1 deficiency

The most common cause of vitamin B1 deficiency is when the rumen grows too many bacteria that produce thiaminase enzymes. These enzymes will destroy any vitamin B1 made in the rumen and the animal. In New Zealand, this occurs when animals change from a rough quality diet to one high in carbohydrates like lush pasture. Other ways in which cattle can become deficient is by eating plants which contain thiaminase or having diets high in sulphates like brassica crops. Deficiency is usually seen in weaned calves in the early summer months. A lack of vitamin B1 will lead to swelling in the brain and causes the brain cells to die.


Usually, the disease only affects a few animals and outbreaks are uncommon. Signs start off being mild and progressively get worse. Initially, calves may separate themselves and stop eating. They progress to being blind, wobbly when walking, being disorientated, head pressing, tremoring and shaking. This eventually progresses to stiff legs, convulsions, collapse then death. Other diseases that can look similar are ryegrass staggers, pulpy kidney and listeria.


A blood test can be done to confirm if it is vitamin B1 deficiency, but unfortunately, it takes a long time for the results so the best method to diagnose is by treating them and looking for improvement. Animals need to be treated with vitamin B1 injections twice daily for at least 3 days. Less severe signs mean a better chance of recovery. Animals who have had severe signs may be left with permanent damage to the brain. Calves that respond will usually recover in 12 to 24 hours.


  • Introduce cattle onto good quality feed slowly.
  • Provide lots of fibre with high carbohydrate diets.
  • Limit sulphates- brassica crops and water with high levels of sulphur.
  • If you have had problems with vitamin B1 deficiency, supplement during risk periods with a thiamine drench.


If you want to discuss treatment and prevention of vitamin B1 deficiency, please don’t hesitate to contact us.