Energy requirements of laying hens in a semi‐arid continental climate 1

A total of 1260 Single Comb White Leghorn layers were used in three experiments, each of 12 months duration. The experimental site was inland, at an elevation of 995 m above sea level and received a mean annual rainfall of 450 mm. The metabolisable energy (ME) contents of the diets used ranged from 2582 to 2918 kcal/kg, lower energies being achieved by the substitution of barley for maize and higher energies by the use of beef tallow.

Differences in dietary energy caused significant differences in egg production and weight in two of the experiments. Increasing ME of the diet caused significant decreases in food intake in two experiments and significant improvements in the efficiency of food conversion in all experiments. Dietary energy was found to affect body weight gains significantly in only one experiment. Energy intake during the summer was 10 to 15% lower than during the winter or spring.

It is concluded from this study that hens of the strain used, laying at a rate of 70 to 75% and weighing about 1·65 kg in a semi‐arid continental climate, require approximately 300 kcal (1·25 MJ) per bird‐days. This requirement varies with the season, being approximately 20 kcal (84 kJ) higher during the winter and 20 kcal lower during the summer.