Relationship between red cell mass, body weight, lean body mass, and body cell mass in growing pigs and beagles

During growth in 55 pigs (from birth through week 12) and 42 beagles studied (from birth through year 1), there was an equally close association between red cell mass (RCM) and body weight, lean body mass (LBM) and body cell mass (BCM); the coefficients of correlation were between 0.94-0.99. The association of RCM with body weight was the result of BCM, extracellular tissue (ECT), and fat, each increasing at a constant rate relative to body weight. The primary relationship appears to be between RCM, the oxygen-delivery system, and BCM, the principla oxygen-using system; and the close association of RCM with body weight and LBM the results of the growth patterns of their components.