Effects of Environmental Temperature on Erythrocyte Numbers and Size

IT IS recognized that environmental conditions influence many physiological factors. The effects of ambient temperature on thyroid activity and the response of the adrenal cortex to cold stress are typical examples. Recent studies indicate that a low environmental temperature may reduce FSH levels in maturing fowl (Subbas and Huston, 1969). Relatively few studies have been made concerning the effects of environmental temperature on the hematopoietic system of birds. Olson (1937) reported a differentiation between the erythrocyte number in the summer and winter, it being increased in the latter. Winter (1935) found that during cold weather the hemoglobin content of the blood of hens increased significantly. Huston (1960, 1965) and also Washburn and Huston (1968) found that the packed erythrocyte volume of birds in a controlled temperature environment was increased in the colder temperature. It has not been established if the effect of temperature on packed erythrocyte volume and hemoglobin content…