Vitamins are defined as a group of complex unrelated fat- and water-soluble organic compounds present in minute amounts in natural foodstuffs (NRC, 2007). There are a variety of B-vitamins, all of which are water-soluble, meaning that excess amounts are excreted through the urine. Not stored in the body.
This group of vitamins plays critical roles in numerous body processes. B vitamins are important for energy metabolism, enzyme function, skin and coat health, neurological health, cellular communication, mood balance, and nervous system function.
B-vitamins are an interesting group of vitamins as the horse, to some extent, can rely on their own production. The process of microbial fermentation, occurring in the hindgut of the horse (large colon and cecum), produces b vitamins. Due to this, dietary deficiency is rare for horses, and in most cases, healthy horses maintained on high-quality forage do not need additional supplementation of b vitamins.
For the group of B vitamins (Thiamine – B1, Riboflavin – B2, Niacin – B3, Pantothenic acid – B5, Pyridoxine – B6, Biotin – B7, Folate – B9, and Cobalamin – B12), the Nutrient Requirements of Horses, only states a dietary requirement for thiamine and riboflavin. However, horses that are maintained on a normal ration with quality forage, and at minimum, a ration balancer or vitamin/mineral premix, should not need additional b vitamin supplementation.
It should be noted that although there are not established dietary requirements for many of the b vitamins, it does not mean that dietary supplementation is not advantageous. For healthy horses, supplementing biotin (vitamin B7), at a rate of 20 mg/day for a 500 kg horse, has been shown in many research studies to improve hoof health and growth rate. Additionally, there are numerous situations that do warrant supplementation with broad spectrum b vitamins.
The situations in which an additional source of b vitamins might be warranted are when horses are on diets consisting of large amounts of concentrates, maintained on low quality forage, are on broad spectrum antibiotics, have compromised digestive health, are under excessive stress or have diminished digestive efficiency. In these situations, working with a qualified nutritionist to determine if your horse might benefit from additional supplementation is recommended.
Beyond quality forage, brewer’s yeast is a commonly used source of b vitamins. There are also many commercial b vitamin supplements available. For these supplements, the vitamins are generally coated to improve stability. Many premixed feed will also include added b vitamin content.
Although dietary deficiency is rare in horses, there are certain toxicities that result in b vitamin deficiencies. For example, horses consuming Bracken Fern often present with a thiamine deficiency.
If your horse is healthy, and consuming a balanced diet with quality forage, then you do not need to supplement them with additional b vitamins. If digestive health is compromised, antibiotics are being used, or forage quality is low, an additional source of b vitamins might be beneficial. If you have questions about your horse’s nutrition, please reach out at balancedbaynutrition@gmail.com
By: Madeline Boast, MSc. Equine Nutrition, PAS
References:
Nutrient Requirements of Horses (2007). Chapter 6: Vitamins.
Reilly, J. D., Cottrell, D. F., Martin, R. J., & Cuddeford, D. J. (1998). Effect of supplementary dietary biotin on hoof growth and hoof growth rate in ponies: a controlled trial. Equine Veterinary Journal, 30(S26), 51-57.
