Preventing Polio (B1 deficiency)

Keep a close eye on weaned calves in the early summer months, especially after shifting them onto lush new pasture.

Polio, short for bovine polioencephalomalacia, is a disease of the brain most commonly caused by thiamine (vitamin B1) deficiency. It is something we see sporadically each year (we have already seen a couple of cases this season, just before Christmas).

Cattle rely on bacteria in their rumen to produce vitamin B1 daily. If factors upset these bacteria, it can lead to either less thiamine being produced or an increase in specific thiaminase enzymes that destroy the thiamine already present in the rumen. This leads to swelling and death of the brain cells.

Who does it affect?

It most commonly occurs in weaned calves, in the early summer months, after sudden changes in their diet, e.g. when shifted onto lush, new pasture. Often we only see a couple of cases within the mob, but occasionally an outbreak can occur.

Signs to look out for

Early signs can include 

  • not eating, 

  • staggering calves, 

  • blindness, 

  • head pressing, 

  • calves that have separated themselves from the mob. 

If not treated, this progresses to the calves becoming more neurological, unable to stand, starting to 'star gaze' and/or having seizures.

Treatment options

Treatment for affected calves involves high doses of vitamin B1 directly into the vein, followed by the same dose into the muscle twice daily for 3 days. An anti-inflammatory is also recommended. 

If caught early, they generally recover quickly. Treatment is only given to those clinically affected, but if an outbreak does occur, there is an oral supplement that can be given to the rest of the mob.

Starting treatment as soon as possible gives the best outcome.

There are a couple of other diseases that present similarly to thiamine deficiency, so make sure you give us a ring to discuss your concerns if you think your calves may be affected.