Studies in Evaluating Energy Content of Feeds for the Chick

Abstract

MITCHELL and Haines (1927a, b) and Fraps and Carlyle (1939a, b, c, 1941a, b, c, 1942) have determined, respectively, the net and productive energy contents of several poultry feedstuffs. Later, with the use of digestibility data and assumed “productive energy values of the effective digestible nutrients” in Calories per gram, designated as factors, Fraps (1946) calculated for poultry the productive energy values of feed ingredients from average composition data. These values have been used extensively during the past decade and found to be useful guides for comparing energy contents of feedstuffs. However, experiments conducted more recently indicated that the determined productive energy values of a diet varied considerably from the values calculated with the use of Fraps' tables (Davidson et al., 1957; Hill and Anderson, 1958). The metabolizable energy values of several feedstuffs for poultry have been obtained directly (Mitchell and Haines, 1927a, b, 1930; Fraps et al., 1940; Olsson, 1950; Halnan, …