Vitamin A (retinol) dogs needed to maintain a normal body tissues, it ensures normal growth, vision, reproduction. With a lack of vitamin A in the diet is intense cornification (keratinization) of epithelial tissue of the digestive, respiratory and genital tract in females. Reduced resistance to infectious diseases of dogs (avitaminoznye dogs are the most susceptible to it). The defeat of the epithelium of the lacrimal glands leads to dry eye cornea (xerophthalmia appears) and reduces the regeneration of visual purple of the retina. At A-avitaminoznyh dogs often observed violation of the function of reproduction: in males sterility in females - in violation of the sexual cycle, poor fertility, birth of weak offspring.
The optimum requirement for vitamin A in adult dogs is 100 IU (international units per gram), in young animals - 200 IU per 1 kg of body weight. And at least one-third of the needs to be satisfied at the expense of the vitamin, two-thirds - due to its provitamin - carotene (1 IU corresponds to 0.3 mg of pure vitamin A or carotene 2 mg). Vitamin A lot of the liver, fish oil, vitamin A in plant feed available. A lot of carotene in carrots, spinach, nettles.