Effect of Vitamin D3 and Calcium on the Reproductive Characteristics of the Turkey Hen

Nine groups of 12 Small-type White turkey hens each were used to study dietary vitamin D3 and calcium and their effect on egg production, eggshell quality, and hatchability. The 3 × 3 factorial arrangement of treatments consisted of three levels of calcium (1.16, 2.25, and 3.34%) and three levels of vitamin D3 (cholecalciferol) at 900, 6,900, and 12,900 International Units per kg. of diet. Increasing dietary calcium to 2.25% significantly improved body weight, egg production and feed efficiency (feed/kg. eggs). The 3.34% level of calcium stimulated an increase in percentage hatchability of fertile eggs and produced the lowest percentage of 28-day embryonic mortalitites. Dietary vitamin D3 in excess of established requirements had no statistically significant effects on any of the parameters studied. Positive correlations were noted between beta-backscatter counts, shell weight, shell thickness and percentage calcium content of the egg. Percentage hatchability of fertile eggs was negatively associated with percentage moisture loss during the first seven days of incubation. The data presented in this paper show no beneficial action in the turkey hen from vitamin D3 fed in excess of recommendations, but dietary calcium in excess (3.34%) promoted an increase in hatchability and a decrease in embryonic mortality.