W. L. English—Birds and Vitamins



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the moult and when breeding, when calcium metabolism is at its

highest, this calcareous protection, if vitamin D and calcium are not

balanced, may be withdrawn and the disease progresses unfavourably.

This explains perhaps the harmful effect of too much sunlight on certain

birds. Too much sunlight or ultra-violet ray may actually precipitate

a fatal attack. I blame the rapid dissolution of a Dusky Parrot to my

misguided efforts with a mercury-vapour lamp. Post mortem examina¬

tion showed this bird was tuberculous.


From theoretical conclusions I should predict that there is some

relation of vitamin D to “ suppressed moult ” in birds.


Rickets


The problem of rickets is complicated by the fact that certain

grains, notably oats, contain a rachito-genic principle. A diet of oats

can actually cause rickets, which makes one wonder why a prominent

aviculturist actually recommends oats for Parrot-like birds. Rats

develop rickets when fed on an exclusive diet of oats, or yellow peas,

or wheat, or rye.


Sterility


Pigeons are sterile with a vitamin B deficiency, and probably in

a vitamin A deficiency.


Absence of vitamin E causes re-absorption of the embryo after

impregnation has taken place.


Occurrence of Vitamins


Generally vitamins occur in the most actively growing tissues of

plants, formed under the influence of sunlight.


Young lettuce and cabbage-leaves contain all the vitamins.

Lettuce is especially rich in the anti-sterility vitamin E. In a wild

state birds live on growing shoots and buds, or on some insect or bird

or animal which lives on these things. Vitamin D can be formed in

its feathers by light. The vitamin problem is complicated by the

individual animal or bird. A prominent authority has said to me :

“ It is not so much a question of giving a balanced diet as of giving

the animal something which it will eat.” Further, one must not expect



