Adaptation to subtropical environments by Zebu and British breeds of cattle in relation to erythrocyte characters

Abstract

Differences in some blood characters between Zebu type cattle, British breeds of cattle, and crosses between these two types are delineated. Zebu type animals tend to have higher packed cell volumes, erythrocyte sodium concentrations, whole blood specific gravities, and gene frequencies for the fast-moving haemoglobin, and lower erythrocyte potassium concentrations and median corpuscular fragilities, than British breeds. The results are discussed in relation to endocrine balance and methods which have been developed for the assessment of adaptation of cattle to tropical and subtropical environments. The concentration of potassium in erythrocytes is suggested as another possible index of adaptation potential in cattle.