The performance of brown egg-type layers fed different protein and energy levels in the tropics

The effects of feeding three protein levels (16, 18, and 20%), each at three metabolizable energy levels (2400, 2600, and 2800 kcal/kg diet), were studied with 990 caged Warren Studler Sex-Sal Link pullets over a 336-day laying period. Dietary protein had no significant effects on hen-day egg production, egg weight, Haugh units, feed intake, feed conversion, feed cost per dozen eggs, caloric intake, egg weights, and final body weight. Protein consumption on all levels of dietary protein was over 20 g per bird per day and increased significantly with increases in dietary protein. Mortality was lowest on the highest protein level. The highest energy level (2800 kcal/kg diet) significantly depressed egg production and feed and protein intake. The feed costs per dozen eggs increased significantly with increases in dietary energy level. Caloric intake and final body weights were similar for the medium (2600 kcal/kg diet) and highest energy levels (2800 kcal/kg diet) but significantly higher than that obtained on the lowest energy level (2400 kcal/kg diet). Egg weights, Haugh units, feed per dozen eggs, and mortality were not significantly affected by energy levels. In spite of the average maximum monthly temperatures, ranging from 26.8 to 35.2 C, annual egg production was about 71 to 73% for the best groups, figures comparable with those obtainable in temperate climates. Egg weight and Haugh units were similar to reported temperate zone values. This experiment supports the use of 16% protein and a metabolizable energy level of 2400 kcal/kg diet for brown egg-type layers.