Raw Rock Phosphate in Laying Rations ,

Abstract

RAW ROCK PHOSPHATE IN LAYING RATIONSHART, McCollum, and Fuller (1909) and Hart, Steenbock and Fuller (1914) reported favorable results from the feeding of rock phosphate in pig rations. However, Forbes, et al. (1921) obtained inferior gains and weak bones with low ash content when pigs were fed rock phosphate in place of limestone and steamed bone meal. Taylor (1929) found that the fluorine in rock phosphate had a very detrimental effect upon dairy animals.Results of the work of Wheeler (1903), Hartwell and Kirkpatrick (1911) and Lewis (1913) indicated that bone ash was superior to raw rock phosphate for chickens. Kennard, Holder, and White (1922) reported that when raw rock phosphate was substituted for steamed bone meal the egg production of hens was not affected, and Buckner, Martin, and Insko (1929) found that although rock phosphate interfered with the early growth of chickens it did not interfere with normal .