997.
Three experiments, each of 10 months' duration, were conducted with individually caged midget (Hy‐line) and conventional (Welp, Babcock and Dekalb) laying hens in order to evaluate their performance and sulphur amino acid (SAA) requirements. Eight replicate groups of five birds each were assigned to a dietary treatment in each experiment.
Various diets, based on corn and soya, were formulated to provide a range of SAA levels from 0.355 to 0.592%. All diets within an experiment were maintained isocaloric and with equal levels of total phosphorus and calcium. Hen‐day production, daily food intake, food/dozen eggs, egg weights and daily SAA intake were measured.
In all three experiments, when SAA requirements were examined as a percentage of the diet, the midget hen was found to have a greater requirement than the conventional strains. However, examination of daily SAA acid intake revealed the reverse situation. In every instance, the average performance of midget hens over all dietary treatments was considerably below that of conventional strains. 相似文献