Estimation of Plasma Volume in Holstein and Jersey Calves

Abstract

The concentration of immunoglobulin (Ig) G in the blood of neonatal calves shortly after birth is a widely used criterion to determine the degree of acquisition of passive immunity. Another method used to determine the biological mechanisms of IgG absorption is calculation of the apparent efficiency of IgG absorption. Estimation of the efficiency of IgG absorption requires the estimation of plasma volume in neonatal calves. Previous estimates of plasma volume in a few calves of varying breeds have been made; the estimates ranged from 7 to 14.5% of body weight (BW). Holstein (n = 97 from four farms) and Jersey (n = 49 from one farm) calves were fed fresh maternal colostrum or colostrum that had been previously frozen. Calves were fed 2L of colostrum at 4.1h (SE = 0.2; range = 0.3 to 11.0h) and 12h later. Plasma volume was measured by determining the concentration of Evans’ blue dye in a jugular blood sample collected 10min after injection of approximately 1.5ml of 1.5% Evans’ blue dye. Factors that affected plasma volume (milliliters) were BW, breed, and age at sampling; r2 of the regression was 0.60. Factors that affected plasma volume (percentage of BW) were BW, breed, and age at sampling; r2 of the regression was 0.08. Mean plasma volume for all calves was 3162ml (SE = 79) and was 9.86% of birth BW (SE = 0.15%). Mean plasma volume was 2250ml (9.71% of BW) and 3623ml (9.94% of BW) for Jersey and Holstein calves, respectively. Body weight was the best predictor of plasma volume.