206 INDIAN JOURNAL OF VETERINARY SCIENCE AND ANIMAL HUSBANDRY [ III, II

In males, spermatozoa become non-motile, then disappear, while germinal epitheli-
um degenerates and testis weight is reduced.

More recently, it has been shown that a deficiency of vitamin A also causes
degeneration of the germinal epithelium, and complete sterility (73, 74, 75). This
effect is more rapidly produced than that of vitamin E deficiency.

From time to time it has been suggested that other vitamins were necessary for
reproduction. It is doubtful, however, whether deficiency of vitamin B has any
specific effect on fertility. The present position (76) appears to be that the effect
on fertility of deficiency of vitamin B is due, not to lack of the vitamin itself, but
to the inanition characteristic of the condition. Vitamin D appears, at least under
certain conditions, to be necessary for normal reproduction in birds, but this is
again probably only a secondary effect associated with the effect of vitamin D on
mineral metabolism and the high mineral requirements for growth of the egg.

It is uncertain whether deficiency of vitamins affecting fertility occurs under
natural conditions. It has been suggested by Velu (77) that deficiency of vitamin
E may be the cause of a condition in sheep in Morocco in which pregnancy occurs,
followed by death and absorption of the foetus. The point does not appear to
have been experimentally investigated. It has also been thought that vitamin E
might be deficient in the rations of farm animals, particularly those stall-fed on
poor rations. Experiments have therefore been made by Graves and Miller (78),
and by Rogers (79) in the United States, and at the Department of Animal Gene-
tics in Edinburgh (communicated) to test whether the feeding of sprouted oats
would influence sterility in cases not attributable to any definite pathological condi-
tion. The results, although suggestive, are inconclusive. (There appears to be
some doubt as to whether sprouted oats contain any considerable amount of
vitamin E.) On the other hand, Vogt-Mφller and Bay (80) claim that a single intra
muscular injection of an ether extract of wheat germ cured sterility in cows kept
under poor conditions on a restricted feed.

Glands of internal secretion. At least two glands of internal secretion have
definite correlations with, and effects on, the ovary (81, 82). These are the thyr-
oid and the anterior lobe of the pituitary. Either a deficiency or an excess of thy-
roid secretion will interfere with ovarian function, causing cessation of ovulation
and sterility. The anterior lobe of the pituitary produces two hormones; one
appears to be necessary for maturation changes in the ovary, the puberty hormone,
and the other promotes luteinising changes. Injection of the former into immature
animals causes early puberty; of the latter, excessive production of lutein with
inhibition of follicular development and sterility. It has been found that extracts
of anterior pituitary may replace vitamin E in a deficient diet, and that the anter.