Serially determined plasma alpha-tocopherol concentrations and results of the oral vitamin E absorption test in clinically normal horses and in horses with degenerative myeloencephalopathy.

The study focuses on the relation between low levels of plasma alpha-tocopherol (vitamin E) and the development of equine degenerative myeloencephalopathy (EDM) in foals, highlighting no evidence of a gastrointestinal tract absorption problem. The research emphasizes that vitamin E deficiency in the first year of life can predispose foals to EDM.

Study Subjects and Methodology

• The study included 9 foals sired by a stallion with EDM and 5 healthy foals raised in the same conditions, acting as control subjects.
• The research used serial monitoring of plasma alpha-tocopherol in these foals during their first year of life.
• An oral vitamin E absorption test was also conducted to rule out absorption issues.

Results and Findings

• It was observed that 8 of the 9 foals from the EDM affected stallion exhibited neurological deficits matching EDM symptoms at least once during the study period. On the other hand, the control foals showed no such symptoms and had normal gait.
• From the age of 6 weeks to 10 months, foals showing EDM symptoms exhibited significantly lower plasma alpha-tocopherol values as compared to control foals.
• The vitamin E absorption test indicated no substantial differences in absorption indices between affected and control horses, negating the idea of a primary gastrointestinal tract absorption issue.

Conclusions

• Based on these study data and considering reported prophylactic and therapeutic benefits of vitamin E, it was concluded that a low plasma concentration of vitamin E contributes to the development of EDM in foals during their first year of life.
• Furthermore, the significantly lower alpha-tocopherol values in the foals did not indicate a primary gastrointestinal tract absorption issue, meaning the problem does not lie in the foals’ ability to absorb the vitamin, but rather their deficiency of it.