The function of vitamin A within the organism is to protect the animal from many diseases and maintain a high fertility level. The animal produces vitamin A through the carotenes contained in grazing herbs, medical herbs and grass silages. The conversion to vitamin A by the animal occurs mostly at the intestinal level and minimally from the liver and the mammary gland. Vitamin A protects the visual capacity and is epithelium-protector, that is, it preserves the oxidation of the sulfhydryl radicals, inhibiting the formation of keratins and greatly influences the fertility of the animal.

In case of vitamin A deficiency degenerative changes occur in the nervous system of the tissues, leading the animal to impaired motor coordination, convulsions, paralysis and weakness.

Generally, this deficiency state is evident in large dairy farms where the increase in nutritional requirements has accentuated the imbalance between forage and concentration in the ration.