Breed Differences in Egg Production of Domestic Fowl Held at High Environmental Temperatures ,

Abstract

NUMEROUS studies at various geographic locations over a period of several years indicate rather conclusively that high environmental temperature is one of the major factors influencing the decline in egg production during the summer months. Winchester (1940), Byerly et al. (1947), Wilson (1948), Ragab and Assem (1953) and others have shown that reproductive performance of domestic fowl is adversely affected by high environmental temperatures. Bruckner (1936) found that in a poultry house artificially heated to a mean temperature of 60°F., the health, body weight, and egg size of the birds were adversely affected. Gutteridge et al. (1944) increased the environmental temperature of laying pullets by the use of artificial heat and insulation over a range of 37.8°F. to 59.9°F. and got no effect upon egg production. Hutt (1938) reported breed differences in susceptibility to extreme heat. White Leghorns withstood drastic increases in environmental temperatures better than did Rhode Island Reds . . .