A Note on the “Animal Protein Factor” and Feed Efficiency

Evidence is available (Bird, Rubin, Whitson and Haynes, 1946; Wiese, Petersen and Lampman, 1948) that supplementation of an all vegetable breeder or growing ration with “the animal protein factor” will result in higher hatchability, increased chick growth and lower mortality in the first few weeks after hatching. Little, however, has been reported on the effect of APF supplementation upon the economy of feed utilization. It was in connection with this aspect of the problem that the following preliminary investigation was undertaken. A standardized APF preparation2 containing 12.5 milligrams of animal protein factor per pound (according to the LLD microbiological assay method of vitamin B12) was used as the source of the animal protein factor. Three different types of ration were fed with and without the APF preparation. Ration 1 was an all vegetable ration consisting of mixed grains with soybean meal. Ration 3 was the same as ration 1 except . . .