Upgrade of egg quality through different heat-combating systems during high environmental temperature

The aim of the study was to find out the effect of various heat-combating systems (HCS) on the egg quality characteristics of commercial laying hens during high environmental temperature of the year. Three hundred pullets were wing banded and randomly divided into 15 experimental units comprising of 20 pullets each. These units were randomly allotted to five treatment groups, replicated thrice according to four heat-combating systems (desert cooling, water sprinkling, time limit feeding, ascorbic acid supplementation), and the control was maintained under the same housing system. The mean values of egg weight, eggshell thickness, Haugh unit, thick albumen height, yolk height, and yolk diameter were calculated. The layers kept under the influence of desert cooling produced eggs with more weight and thicker shells than those under other systems. Results of the present study did not show any difference in the shell thickness between water sprinkling and ascorbic acid supplementation as compared to the control group. Haugh unit and yolk index values obtained from the layers kept under various HCS did not significantly differ from those of the control group. All HCS significantly reduced the occurrence of blood spots in the eggs as compared to the control. All the treatments in general markedly reduced the incidence of meat spots in the eggs especially with the supplementation of ascorbic acid being the most effective. Among all of the treatments, the desert cooling system proved to be the best for producing better-quality eggs during hot periods of the year with less humidity.