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- Are your sheep polio affected?

This year we are hearing more farmers ask the question “Why are my sheep acting like they are blind and staring off into the distance?”. While we can’t be 100% sure without seeing the animals, there is a possibility that it could be ‘polioencephalomalacia’ or PEM, which is a result of the body not producing or absorbing enough Thiamine or B1 Vitamin.

Both cattle and sheep can be affected with younger animals more prone to the deficiency due to the limited function of their rumen. Clinical signs of this illness are disorientation, wandering, blindness, and/or star-gazing.

While PEM can occur in different scenarios it usually occurs in conjunction with low Thiamine levels in the animal. Some of the factors that seem to be present in many occurrences of this issue are:

  • high grain feeding diet,

  • high sulphur content in the drinking water, and

  • animals that are consuming a large number of summer weeds that minimize the function of the liver.

Blind and star-gazing animals have only recently (last 3-4 years) appeared to be an issue, and as most normal functioning adult ruminant can produce enough Thiamine in the rumen it begs the question what has changed?

Whilst we don’t have a definitive answer there are a couple of schools of thought:

  • Now that, as farmers, we have recognized the importance of getting our ewes in better body condition score before joining and lambing, we see more grain being feed to animals. From what we know about rumen bugs, the ones that digest grain don’t produce large amounts of thiamine from that diet.

  • Some summer weeds can produce a counteractive product called thiaminase which is sometimes 100 times stronger than thiamine. As we have had plenty of summer rain in the last few years more weeds have been able to grow.

While this is not conclusive, we do know that we can supply Thiamine for your stock via the TPM Bovine & Flock Boost loose lick range. We also can customise your product with increased levels of Thiamine, if your stock is presenting deficient.

So for more information on customising to your stock's nutritional requirement, or simply to balance your ration with more thiamine to aid in the prevention of PEM, please contact one of our TRAC experts.


Our Consultants


Mark Facy

0427 243 320

Owen Rees

0429 437 823

Mikaela Baker

0457 243 319


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