Calcium Requirements of the Turkey Breeder Hen1

LOW EGG production, fertility and ' hatchability in turkey breeder hens has stimulated researchers in recent years to attempt to find ways of increasing the reproductive potential of the turkey hen. The effects that dietary calcium has on chicken egg production and hatchability have been well established, but little re-search has been conducted with mineral re-quirements for turkey breeders. Published calcium requirements for the turkey breed-er hen have been based mostly on research with chickens. Jensen et al. (1963) reported that egg production of turkey breeders was de-pressed when a diet containing less than 1 % calcium was fed. Increasing the calci-um levels beyond 1.75 % did not increase production, and levels of 2.5 or 3.25 % cal-cium caused a significant reduction in hatchability. In a later experiment Jensen et al. (1964) observed no detrimental effects in either egg production or hatchabil-ity when levels of calcium up to 6.25% were fed. Balloun and Miller (1964) re-ported that hatchability of turkey eggs was depressed by either 1.5 or 3.0 % calcium. They reported optimum performance with 2 or 2.5 % calcium. Atkinson et al. (1964) obtained the best reproductive performance with 3.08 % calcium and 0.75 % inorganic phosphorus when large-type turkey hens were kept in floor pens. With hens in cages, best results were obtained with diets con-taining 2.54 % calcium and 0.61 % inorgan-ic phosphorus. Waibel (1965) found n