Total Circulating Erythrocyte and Plasma Volumes of Ducks Measured Simultaneously With Cr51

Abstract

EARLIER reports of total blood, plasma, and erythrocyte volumes in birds have been reviewed by Sturkie (1965). There are large differences in values with different species and with different methods of analysis. In many cases, dye-dilution procedures for plasma volume have not included a correction for the dye lost from circulation between injection and sampling. Most determinations of total blood volume have been indirect, through a calculation using venous hematocrit and either plasma volume or erythrocyte volume.Since in mammals the whole-body hematocrit is different from the venous hematocrit (Ebert and Stead, 1941), such indirectly-determined blood volumes in birds may be in error by perhaps 10%. No simultaneous determinations of erythrocyte and plasma volumes, and no ratios of whole-body hematocrit to venous hematocrit, have been reported for birds.An unsuccessful Cr51 tag-dilution procedure for total plasma and erythrocyte volumes in man (Read and Gilbertsen, 1957; Lajtha, personal communication) has been .