a) Microorganisms and vitamins found in the digestive system of some of the farm animals are of the type that can synthesize very little or no vitamins. In fact, since these microorganisms need vitamins in the feed, they compete with the animal as a host in this respect.
b) Vitamins are inevitable elements of intense metabolic reactions in farm animals. Since they participate in many reactions in metabolic events, they are essential elements of energy and protein metabolisms and therefore life.
c) It has been found that some vitamins play an important role in resisting the stresses caused by today’s intensive production conditions of farm animals.