Abstract

SINCE it was first unequivocally shown that the milk yield of lactating cows could be increased by feeding dried thyroid gland1 or injecting thyroxine2,3, many experiments (see Reineke4 for review of some of them) have been carried out on the practical use of thyroid-active substances for increasing the milk yield of cows over limited periods of time. Dried thyroid gland and, more recently, iodo-casein (an artificially prepared thyroid-active protein) have been preferred to synthetic thyroxine for this purpose, because of the high cost of the latter and the belief that its activity was not great by the oral route.

References

1. Graham, W. B., jun., J. Nutrit., 7, 407 (1934).
2. Graham, W. B., jun., Biochem. J., 28, 1368 (1934).
3. Folley, S. J., and White, P., Proc. Roy. Soc., B, 120, 346 (1936).
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7. Pitt Rivers, R., and Lerman, J., J. Endocrinol., 5, 223 (1948).