Vitamin B12

Mechanism

Cobalamin acts as methylcobalamin and adenosylcobalamin as coenzyme of methionine synthase and methylmalonyl-CoA mutase and is thus involved in blood formation, amino-acid and fatty-acid metabolism as well as in the normal function of the nervous system. In the horse an external supply is nutritionally hardly necessary, because the hindgut flora synthesises cobalamin itself (hindgut fermentation) and subsequently absorbs it. A precondition for this is an adequate cobalt supply of the ration, since the central cobalt atom of the molecule is incorporated by the microorganisms; a cobalt deficiency can therefore indirectly limit B12 synthesis. Plant feedstuffs contain practically no vitamin B12, which is why the microbial endogenous synthesis represents the decisive supply pathway. Supplementation is mainly a subject of discussion in case of cobalt deficiency, disturbed gut flora, high performance or pregnancy.

Cautions

• · Microbial endogenous synthesis in the hindgut usually meets requirements with healthy digestion — the main lever is the cobalt supply
• · Plant feed provides practically no B12; in case of disturbed gut flora or cobalt deficiency check the supply
• · Parenteral high-dose applications fall within the veterinary domain, not within complementary feed

Sources