Last Updated : September 23, 2021

What vitamins do dogs need

Vitamins are essential substances, without vitamins the dog’s body cannot thrive. When the dog diet is deficient in any of the vita­mins, certain disease conditions arise. The vitamins are called either by their technical names or, simply, by various let­ters assigned to them. Thus we speak of vitamins A, B, C, D, and so on. The public has been subjected to so much mislead­ing information about vitamins by the press, radio, and tele­vision that it would be well to give a few notes of re­liable scientific data about them.

Vitamin A

Vitamin A is essential to the maintenance of health in the dog, and when the diet is deficient in this substance, a variety of disease manifestations may ensue. These disease condi­tions will occur only when the deficiency is well marked. Where the deficiency is only slight, distinctive symptoms will not be apparent and its diagnosis can be established only by technical laboratory procedures.

Probably the commonest disease associated with vitamin A deficiency is the eye condition known as xerophthalmia. This is characterized first by a watery and glassy appearance of the eyes, and by a marked congestion of the eye membranes. The tear ducts become blocked and infection ap­pears. The surface (cornea) of the eyeball becomes inflamed, develops a watery swelling, and finally ulcerates. In the advanced stages of eye-tissue degeneration in xerophthalmia, permanent blindness may result.

Growth and reproduction may also be adversely affected by a vitamin A deficiency, and it is occasionally a cause of sterility in dogs. Growth of the ear bones may also be im­paired. Deafness can sometimes be traced to this deficiency. Tooth and gum involvements, and a tendency to the forma­tion of kidney and bladder stones, may also be occasioned by a lack of this vitamin.

Where these conditions have not progressed too far, they respond readily to treatment, which consists simply of alle­viating the symptoms and incorporating sufficient quan­tities of vitamin A in the diet. Cod-liver oil and halibut-liver oil are excellent sources of vitamin A. Carrots, lettuce, tomatoes, corn meal, and alfalfa meal also possess consider­able quantities of an assimilable form of vitamin A. For the normal animal, a suitable diet should include sufficient vita­min A to prevent any of the deficiency conditions we have mentioned. That is why the section on feeding in this book details the specific doses of cod-liver oil that should be fed to puppies. For the determination of a balanced ration either to prevent or to treat vitamin A deficiencies, consult your veterinarian.

Vitamin B-L, Thiamin Chloride

Vitamin B-l is another vitamin essential to the mainte­nance of dog health. Diets that are deficient in this vitamin may result in loss of appetite, failure to excrete regularly, lowered resistance to infection, paralysis of the hind legs, pos­sibly running fits (or as it is variously known fright dis­ease, barking fits, furious fits, canine hysteria), convulsions, and death.

The main sources of this vitamin are meat, brew­er’s  yeast,   and  wheat  germ.   The  latter  two  substances are commonly incorporated in commercial dog foods to pro­vide the amount of vitamin B-l necessary to prevent pos­sible deficiencies.

Dogs that are fed table scraps usually get sufficient quantities of this vitamin to meet their needs. It is therefore apparent that deficiencies of this vitamin can occur only under fairly extreme cases of improper nourish­ment, which means that vitamin B-l deficiencies are not too commonly met with in household pets whose owners make even a minimal effort to feed them properly.

Vitamin B-2, Riboflavin

This is another essential vitamin. Deficiencies of this vitamin may result in certain forms of liver trouble, anemia, muscular weakness in the hind legs; dermatitis on the hind legs, chest, and abdomen; and sore eyes.

The best natural sources of vitamin B-2 are liver and yeast. Other excellent sources are soy flour, beans, eggs, wheat germ, cheese, and milk. Dogs that are fed meat and milk or a standard dog food will rarely be affected by a deficiency of this vitamin. It is therefore fairly uncommon in the well-kept house dog.

Niacin Or Nicotinic Acid

Deficiencies of this vitamin will result in a disease of dogs called black tongue. This disease is related to pellagra in humans, from which a synonymous term for niacin deficiency has been coined: the Pellagra Preventive Factor. Deficiencies of this vitamin are extremely rare in ordinary household dogs since commercial dog foods and meat have more than enough of this vitamin to meet the dog’s needs. This is a problem found only in areas of extreme poverty.

Vitamin B-6, Pyridoxine

Not much is known about this vitamin. Deficiencies of it result in certain forms of anemia. It is not common in the ordinary house dog since it is present in sufficient quantities in the fresh or commercial foods commonly fed to dogs. The main sources of pyridoxine are wheat germ, yeast, egg yolk, fish, liver, green vegetables, and whole wheat.

Pantothenic Acid

Deficiencies of this vitamin may result in loss of muscle control of the legs and unhealthiness of the gums, it is present in liver, yeast, and crude molasses. Deficiencies are uncommon.


This vitamin is present in liver, eggs, soybean meal, and yeast. Deficiencies result in improper growth and liver trou­ble, but the adequate supply of this vitamin does not pose a very significant problem for dogs.


This vitamin is not important in dogs since only minute quantities are required and these are readily available. Lack of biotin results in a progressive paralysis.

Folic Acid

The data for the dog’s requirement of this vitamin are very limited. Deficiencies result in anemia and breeding troubles, but this has been determined in other animals rather than the dog.

Vitamin B-12

Vitamin B-12 is essential to the health of dogs. Deficiencies of it can lead to certain forms of anemia. Natural sources are liver, yeast, meat scraps, and some fish oils. It does not pose much of a practical problem.

Vitamin C

Dogs manufacture their own vitamin C and therefore have no special need for this vitamin. Humans that have a defi­ciency of this vitamin develop scurvy, which is cured by fresh fruit juices and vegetables. No disease resembling scurvy appears hi the dog. However, the bodies of dogs will occa­sionally fail to manufacture sufficient quantities of vitamin C, and variable degrees of irritation will result in the membranes of the mouth and gums. This condition responds readily to proper doses of this vitamin.

Vitamin D and Rickets

Any person who has ever raised a child knows that the physician will prescribe some sort of vitamin supplement for the infant. Though the vitamins serve as a general body tonic, one of their main purposes is to prevent rickets. Rickets in dogs and children are very similar conditions.

In dogs, rickets is a nutritional disorder characterized by various bone deformities. It is especially evident in young puppies from weaning time to one year of age and is noted more often in larger breeds than in smaller ones. It is readily amenable to treatment in its early stages, becomes more re­sistant as the disease progresses, and may terminate in per­manent deformity. It is apparent, therefore, that veterinary intervention is essential as soon as the symptoms are recog­nized.

The disease is caused by a lack in the diet or the improper assimilation of calcium and phosphorus and/or vitamin D. This results in deficient bone development. The leg bones become soft and bend, giving the animal a bow-legged ap­pearance, and the ends of these bones become spongy, thus making the joints appear swollen. The animal may arch its back, maintain a crouched stance, show retarded dental development, develop a tendency to bloat, and have attacks of diarrhea. The animal will generally express an air of be­nign lassitude and will be inattentive to its surroundings.

A Severe Case of Rickets
A Severe Case of Rickets

Though rickets is readily discernible by clinical symptoms, positive diagnosis is established by X-ray. The X-ray is especially valuable because the disease can be diagnosed in this manner even before the clinical symptoms appear, and thus can be treated before any deformities manifest them­selves.

Rickets is treated by incorporating into the diet the ele­ments in which it is deficient, or by correcting the causes of improper assimilation. This can be done by feeding fresh meat and vegetables and backing these up with a standard mineral supplement. Therapeutic doses of vitamin D are additionally supplied in the form of cod-liver oil, halibut-liver oil or any similar preparation.

It is always easier to prevent rickets than to attempt to cure it. As mentioned earlier, it is advisable to give puppies half a teaspoonful of cod-liver oil a day, and to dogs weighing over twenty pounds one whole teaspoonful a day. The very large breeds, such as Great Danes and St. Bernards, may be given two teaspoonfuls a day. This should be continued until the animal is about a year old. At this age the permanent bone formation is established, and the subsequent vitamin D re­quirement can be amply supplied by the food alone.

The discussion so far has been on the infantile form of rickets. Mature animals suffer from a similar sort of disturb­ance, due to the same deficiencies, called osteomalacia or late rickets. In this instance, too, the softening of the bones may lead to lameness and deformity. However, since the calcium, phosphorus, and vitamin D requirements are much smaller in older dogs than younger ones, these manifestations are less likely to occur. Late rickets is less common than infantile rickets and much less responsive to treatment.

Vitamin E

Vitamin E is essential to the preservation of muscles and is reputed to improve reproductivity in animals. It is present in liver, lettuce, and especially in wheat germ oil. It is well to mention that cod-liver oil may destroy the vitamin E in the dog. Thus large doses of cod-liver oil should be judi­ciously avoided. There is a synthetic form of vitamin E on the market which has been used very successfully in treating deficiencies of this vitamin.

Vitamin K

Though vitamin K is essential, no known disease has been recognized in dogs as a result of vitamin K deficiency. Alfalfa leaf meal is rich in this vitamin. Vitamin K appears to be related to the clotting of the blood.

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