Vitamins are essential substances, without which the body cannot
thrive. When the 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 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.
the Vitamin B Complex 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.
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.
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.
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.
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
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 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.
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 in 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
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
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
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
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.
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 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.
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