A Chick Growth Factor in Cow Manure III. Its Occurrence in Eggs.

If the chick growth factor in cow manure is supplied in the diet of hens, it is transmitted by them to their eggs and hence to their chicks (Rubin and Bird, 1946). The present note is a report of some preliminary experiments to determine the distribution of the growth factor of cow manure in hens’ eggs. Hens were fed diets #311 or #312 which were described in a previous report (Bird, et al. 1946). Diet #311 was deficient in the growth factor and diet #312 contained an ample quantity of it. Eggs laid by these hens and certain fractions prepared from the eggs were assayed for their content of the growth factor by feeding to growing chickens as supplements to the basal diet used in previously reported experiments (Rubin, et al. 1946). Groups of twelve cross-bred chicks were used. All of them were fed the basal diet for two weeks . . .