Calcium Metabolism in the Laying Hen

Abstract

Four experiments were conducted using 301 mature egg-type hens to determine the effect of calcium source, size, and dosage level on CaCO3 retention in the digestive system. The results indicated that particle size of CaCO3 had a definite influence on CaCO3 retention in the gizzard. However, there were no significant differences in CaCO3 retention in the gizzard between hens fed hen-sized CaCO3 or between hens fed pullet-sized CaCO3 regardless of whether the calcium was derived from oyster shell or limestone. The quantity of CaCO3 dosed seemed to have little influence on the metering of CaCO3 from the gizzard. The results also indicated that 87 percent of the CaCO3 metered out of the gizzard in a single 24-hour period was metered out between 8 a.m. and 8 p.m. with very little of the CaCO3 being metered out of the gizzard at night.