The Effect of Environmental Temperature and Humidity on the Calcium Balance and Serum Calcium of Laying Pullets

Abstract

BENNION and Warren (1933) and Warren and Schnepel (1940) reported that shell thickness is reduced markedly if hens are subjected to high environmental temperatures. Their experiments further suggested that the depressing effect of high temperature is accentuated by high humidity.The mechanism or mechanisms which cause poor shell quality at high air temperatures are still not definitely established. Conrad (1939) found that blood calcium levels were reduced at high environmental temperatures. From this evidence Warren and Schnepel (1940) concluded that: “The decrease in shell thickness when the birds are subjected to high temperatures is probably due to a reduction in calcium content of the blood.” Warren and Schnepel (1940) also reported that hens kept at 95°F. consumed about 26% less feed than hens kept at 60°F. It is possible that this reduction of feed intake is at least partially responsible for the poor shell quality at high air temperatures. Finally, …