The Effect of Dietary Fat Level on the Rate of Mortality in Caged Layers

ALTHOUGH the advantages of fat supplementation of broiler rations have been amply demonstrated, the value of thus increasing the energy level of laying rations is questionable. It has been reported by Weiss and Fisher (1957) and Donaldson and Gordon (1960) that rations containing high levels of fat fed to laying birds may result in obesity and fatty livers leading to a high rate of mortality. The present paper summarizes the data on mortality obtained in an experiment in which birds were kept in cages and fed diets supplemented with different levels of fat from day-old to 3 years of age. EXPERIMENTAL Starting, growing and laying rations were formulated according to Table 1. The rations were calculated to contain 20, 16.5 and 15 percent protein respectively. Each type of ration was adjusted to contain 2.5, 7.5 and 12.5 percent of fat. The two higher levels of fat were attained by the …