The Effect of Dietary Calcium Level on the Efficiency of Ascorbic Acid in Maintenance of Egg Shell Thickness at Increased Environmental Temperatures ,

REVIEW OF LITERATURE IT HAS been demonstrated previously that dietary ascorbic acid was effective for maintaining egg shell thickness under heat stress conditions (Thornton and Moreng, 1958, 1959). Since the basal rations used in those experiments were rather low in calcium under present field conditions (calcium approximately 2.3 percent), it was believed important to test the response of ascorbic acid at varying calcium levels. Petersen et al. (1959), reported that increasing the calcium level above 2.25 percent of the ration resulted in significant increases in egg specific gravity values. It appeared that this increase was most pronounced at a level of 3.75 percent calcium. Levels of 4.50 and 5.25 percent showed some additional increase over the 3.75 percent level but was of less relative magnitude. Tyler (1946) found no difference in egg production or shell thickness in 6.0 or 3.0 percent calcium diets. Soft shell eggs as well as other …