Influence of Calcium in Laying Rations on Shell Quality and Interior Quality of Eggs

STRENGTH of shell is an important factor in handling and transporting of eggs. One of the useful and economic traits of a laying hen is an ability to produce eggs with strong shells. Physiologically, it means that calcium metabolism must be efficient. The amount of calcium in the laying ration has a marked effect on shell quality and egg production (Norris et al., 1934; Miller and Bearse, 1934; Evans et al., 1944). Based on past experiments, the National Research Council (1960) has recommended 2.25% calcium as the dietary requirement for the laying hen, however, recent reports indicate a higher requirement of 2.75% (N.R.C., 1966). Peterson et al. (1959) concluded that hens fed 3.38% calcium showed a highly significant increase in the specific gravity of eggs as compared with lower levels of calcium. They further suggested that 3.75% calcium in laying rations would be adequate for environmental temperatures below 70°F. and . . .