Evaluation of Dietary Calcium Requirements in Fayoumi Laying Hens

The experiment was carried out in poultry experimental station belonging to NRC, Cairo, Egypt. A total of 120 Fayoumi layers, 45 weeks old, were randomly divided into four equal groups. Each group included three replicates (10 hens in each). The first group was fed the control diet containing 3.3% gram Ca, whereas, the other three received diets containing 2.8, 2.6 and 2.4% gram Ca, respectively. Calcium was added to the ration in the form of limestone. The results of the present study clearly indicated that there were no significant differences among groups fed diets containing different levels of Ca (2.4 up to 3.3 g %) in egg production, egg weight, egg mass, daily feed consumption and feed conversion efficiency (P > 0.05). The control group displayed the lowest percentage of fertility (59.33) and hatchability (42), and the highest percentage of embryonic mortality (17.33), while the best results of the reproductive performance were recorded from the fourth group fed diet containing 2.4% Ca. Measurements of egg characteristics indicated no significant differences among groups (P > 0.05); however, yolk color was slightly improved in the fourth group at six weeks of treatment. Shell percentage and thickness tended to increase in the fourth group par-ticularly after 12 weeks of treatment. In conclusion, dietary calcium levels (2.4 up to 3.3%) did not signifi-cantly influence egg production, egg mass, feed conversion efficiency and egg quality (P > 0.05). However, low level of dietary calcium (2.4%) has improved egg fertility, hatchability and shell percentage and thick-ness. A percentage of 2.4% of calcium in the diet is recommended for Fayoumi laying hens.