Effect of Dietary Energy Concentration on Performance of Heavy Egg-Type Hens at Various Densities in Cages

Abstract

Three dietary energy levels (2,737, 3,003, 3,322 kcal./kg.) were fed to heavy egg-type hens housed in cages at densities of 1,320, 660, and 440 cm. 2 of floor area per hen.Increasing the number of hens per cage reduced egg production. This was most pronounced with three hens per cage during the latter part of the experiment. Final body weight was reduced only with three hens per cage, and occurred to a greater degree at the end of the experiment. Mortality increased at the higher hen densities due to Marek's disease and lymphoid leucosis. Hen density did not significantly affect egg weight, shell strength, Haugh units or meat and blood spots.Dietary energy level did not significantly alter overall hen-day egg production. However, egg production on the highest dietary energy level declined more rapidly in the latter months. Therefore, a high dietary energy content was not conducive to sustained egg production.There were no significant interactions between hen density and dietary energy level. But, with two or three hens per cage, egg production was consistently lower for hens fed the highest dietary energy level.As dietary energy level increased, feed intake decreased and feed efficiency increased. But energy intake increased resulting in heavier hens on the highest energy ration.The highest dietary energy caused an increase in egg size during the mid-part of the experiment. Otherwise, energy level did not affect egg weight, shell strength, Haugh units or blood and meat spots.It is concluded that although increases in dietary energy levels result in increased energy intakes and body weights of hens, high energy rations will not reverse the downward trend in egg production as density of caged hens increases. To the contrary, feeding of high energy rations to hens housed at high densities in cages may not be advisable, since egg production was consistently lowest under these conditions.