B Vitamins in Horses

B Vitamins in Horses
5 July 2017 | Foran Equine

Vitamins are crucial for health and body function in the equine diet, with roles in performance, growth, reproduction, energy maintenance and immune system function. B vitamins are a group of water-soluble vitamins that each have unique chemical names and functions, collectively known as the B vitamin complex (this article will refer to the B vitamin complex as B vitamins). The B vitamins have important roles in cell metabolism, processing protein, carbohydrates and fats as well as nerve transmission, energy metabolism and red blood cell production.

Eight of the B vitamins are considered essential, which is why it can seem some are missing from the numerical list of B vitamins on a horse feed or supplement. B vitamins commonly supplemented in the equine diet are:

Scientific Name
Main Function
Vitamin B1
Plays a key role in carbohydrate metabolism; a co-enzyme which supports the change of nutrients into energy.
Deficiencies in Vitamin B1 can lead to inappetence and nervousness
Vitamin B2
Supports energy metabolism and production of immune cells
Vitamin B3
Niacin (or Nicotinamide)
Energy transfer in the body
Vitamin B5
Pantothenic Acid (Calcium Pantothenate)
Breakdown of fat and protein synthesis
Vitamin B6
Involved in amino acid metabolism, plays a role in haemoglobin production and is an essential factor in energy production
Vitamin B7
Supports cell integrity
Vitamin B9
Folic Acid
Cell division and growth. Red blood cell production
Vitamin B12
Promotes red blood cell production; involved in protein metabolism and in the metabolism of fats and carbohydrates


B Vitamin Sources

As they are water-soluble, B vitamins are not stored by the body and any excess supply is excreted in the urine. All B vitamins are essential to horses and are therefore needed in the diet on a regular basis. B vitamins are plentiful in grass and some cereal grains. Microorganisms, primarily in the hind gut, synthesise B vitamins which are absorbed through the intestinal wall.

Healthy adult horses can usually produce adequate levels of B vitamins – deficiency has not been described in horses except under experimental feed deprivation studies. However, there is a difference between the minimum requirements to prevent deficiency symptoms versus optimum requirements for maximum performance

Many factors can influence the availability of B vitamins; they are produced by the microflora of the hindgut and therefore if the microbial population is compromised as it often is with performance horses, vitamin B availability can be reduced.


B Vitamin supplementation may be beneficial in situations such as:

  • Horses with reduced appetite
  • Horses with diets low in fibre or receiving poor-quality forage
  • During times of stress or high exertion, for example travelling, racing and competing
  • When disease, parasitic burden or poor digestive health (e.g. diarrhoea or antibiotic use) compromises the hindgut microflora
  • Dietary changes which may alter the levels of fibre, protein and carbohydrates in the hindgut
  • Elderly horses with reduced digestive ability

B Vitamin Supplementation

As key nutrients regulating energy release, B vitamins can impact a horse’s energy levels and performance. They have also been shown to impact appetite and nervous behaviour, qualities which are important to high performance equine athletes.  Supplementing B vitamins via the diet can be very effective, they are readily absorbed and utilised when needed and as water soluble vitamins they are very safe and not at risk of over-supplementation.

At Foran Equine we produce a number of supplements containing B vitamins aimed at helping particular scenarios that arise, some of those products include:


B-Complete contains all vital B vitamins essential for blood cell formation and optimal metabolism, maximising the diet for energy production. It is suitable for any horse with a requirement for maximum energy production and can also safely promote appetite during times of decreased stress and fatigue, for example when travelling. The palatable liquid formula supports digestive function and safely promotes appetite.

Muscle Max

Muscle Max is a palatable liquid suitable for all performance horses, youngstock and during sales preparation to support muscle development. Using essential amino acid L-Lysine, Vitamin E, Selenium and B vitamins Muscle Max aids muscle build up, helps to guard against cell injury and optimise protein and energy use within the body. Muscle Max can also be beneficial in breeding stallions and broodmares as high levels of antioxidants coming from Vitamin E and Selenium support fertility, while B vitamins assist in the utilisation of energy and L-Lysine is a key component of mare’s milk.


Manthe, B. N. and Youngs, C. R. (2013) An Overview of Vitamin Requirements of the Domestic Horse. Natural Sciences Education, 42(1), 179-184. DOI: 10.4195/nse.2012.00002