The Value of Thyroprotein in Starting, Growing and Laying Rations

SEVERAL reports have appeared which suggest that thyroprotein, (iodinated casein) may have beneficial effects when fed to young chicks and, during the summer months, to laying hens (Parker, 1943, Irwin, Reineke and Turner, 1943, Turner et al., 1945, Turner, Irwin and Reineke, 1945, Gutteridge and Pratt, 1946, Gutteridge and Novikoff, 1947, Wheeler, Hoffmann and Graham, 1948). No experimental data are available, however, on the effect of feeding thyroprotein during the “growing period,” but Turner (1947) has recommended in a popular article that, “For growing pullets, the . . . (thyroprotein) feeding can continue at the rate of 15–20 grams per hundred pounds of their total feed until the approach of sexual maturity. Then the . . . (thyroprotein) can be cut to 10 grams per hundred pounds of their total feed.” The present paper reports on the effects of feeding thyroprotein during the 12 weeks period (12 to 24 . . .