The Influence of Dietary Calcium Level and Supplementary Ascorbic Acid and/or Dienestrol Diacetate upon Performance of Egg Production Type Hens

IT IS generally accepted that egg shell quality declines with age of bird (Sturkie, 1954) and with increased environmental temperature (Miller and Bearse, 1934; Warren and Schnepel, 1940; and Wilson, 1949). The cause for this decline in egg shell quality is not known; however, recent research work has indicated that certain dietary alterations may prevent a portion of this decline. Thornton and Moreng (1958Thornton and Moreng (1959) reported that the addition of ascorbic acid to the laying diet would prevent a portion of the decline in egg shell quality due to heat stress. Petersen et al. (1960) reported that 2.25 percent calcium, as suggested by the National Research Council (1954), was not adequate for the University of Idaho strain of Single Comb White Leghorn hens. These workers found that 3.75 percent calcium was necessary for good shell quality with environmental temperatures of less than 70°F., and with higher temperatures a calcium intake…