What Does It Do?

B₁₂ is vital for enzyme function and for fat, protein and carbohydrate metabolism. B₁₂ is also required for the formation of blood cells and amino acids.

Nutritional Requirements:

Since it is extremely difficult to assess the true vitamin B₁₂ status of animals the accuracy of any measurement of requirement is doubtful. Most research on the vitamin B₁₂ requirement arrive at a value of 10 mg/kg feed dry matter for maintenance.

This should be regarded as the requirement  for average horses and, as with other B vitamins, should be increased for hyperactive and performance horses.

Where Does My Horse Get B₁₂?

It is synthesized by micro-organisms in the horse’s hindgut but additional B₁₂ is obtained through consumption of feedstuffs, especially good quality forage. As with other B-vitamins,  B₁₂ may not be absorbed efficiently by the hind gut so horses are dependent on a regular dietary supply.

What About B₁₂Toxicity?

With water-soluble vitamins such as the B vitamins, there are no body stores and any excess vitamin B₁₂ is excreted within 48 hours of intake. As far as I could determine, there has not been any reports of toxicity in horses. 

What About B₁₂ Deficiency?

Deficiencies with B₁₂ are more likely than toxicity because it is not a fat-soluble vitamin and daily intakes are required.  However, most horses get an adequate amount in their diets as long as high quality forage is a good part of it.  If the horse’s diet is dependent on grain or commercial feed concentrates additional B₁₂ might need to be supplemented.  It also should be noted that during normal feed mixing there can be about a 10% loss of B₁₂ and if the feed process includes extruding, the loss of B₁₂ may be as much as 30%.

~Peace and Good Feed,

The Nerd