Too little Vitamin B1
Vitamin B1 (Thiamine) is under normal healthy conditions produced in sufficient quantities by the large intestine of the horse. When stressed or when workloads are high B vitamin production can be reduced and supplementation is recommended. The ratio of grains to forage also influences B vitamin production with high grain and low forage diets negatively impacting on production. Always feed adequate forage.
Solutions: Concentrates and most vitamin/mineral mixtures for horses are supplemented with vitamin B1. Bakers yeast and brewers grain are good sources of B1.
Too much Vitamin B1
Moderate over feeding of vitamin B1 have no known negative effects.
Solutions: Consider reducing the intake of high B1 feeds and supplements