Thiamine (Vitamin B1)

Thiamine, also known as Vitamin B1, is a water-soluble vitamin essential for carbohydrate metabolism, nervous system function, and energy production in horses. It plays a critical role in the conversion of glucose into ATP, the primary energy source for cells, by acting as a coenzyme in the Krebs cycle. Thiamine is also necessary for the proper functioning of the nervous system, as it helps regulate neurotransmitter activity and nerve impulse transmission.

Horses naturally produce some thiamine through microbial fermentation in the hindgut, and additional dietary sources include cereal grains, wheat bran, and brewer’s yeast. Deficiency is rare but can occur due to prolonged antibiotic use, excessive grain consumption, or ingestion of plants containing thiaminase enzymes (such as bracken fern and horsetail), which degrade thiamine. Symptoms of deficiency may include weight loss, muscle tremors, incoordination, and nervous system disturbances. In such cases, thiamine supplementation in the form of thiamine hydrochloride or thiamine mononitrate may be beneficial. As a water-soluble vitamin, excess thiamine is excreted in urine, making toxicity unlikely, though balanced supplementation is advised for optimal health.