Efficiency of the utilization of the energy of food in laying hens

SUMMARY The efficiency of utilization of the energy of food in White Leghorn laying hens for egg production was measured. A ration with a gross energy of 4469 kcal/kg dry matter and 19·4% crude protein had a metabolizable energy of 80·1±1·7% of the gross energy, and 78·5±5·3% of the metabolizable energy was present as net energy. The maintenance requirement of metabolizable energy of White Leghorn hens weighing 1·723±48·5 kg and a production of 19·3±0–49 eggs per month was 125·8 kcal/kg 0·75 /24 hr. The energy cost per g of protein and fat synthesized by laying White Leghorn hens was estimated to be 7·20 and 12·13 kcal metabolizable energy respectively.