Duck Disease Studies I: Blood Analyses in Diseased Birds

Abstract

It has long been observed that ducks and other migratory birds which settle about inland marsh lands and shallow lakes reputed to contain “alkali waters” develop characteristic symptoms resulting frequently in heavy mortality. A systematic study of this disease has been proposed through the co-operation of the California Fish and Game Commission, the Hooper Foundation for Medical Research, and the Department of Pharmacology of the University of California Medical School. This report is the first of a series to be made in connection with this study.

This report deals with blood chemistry studies on diseased birds from the San Joaquin Valley district in comparison with normal healthy birds. Four blood constituents, non-protein-nitrogen, uric acid, blood sugar, and chlorides, have been studied on 13 normal and 15 diseased ducks of the pintail or sprig species (Dafila acuta). Blood samples were taken directly from the heart and determinations made on protein-free filtrates according to the Folin and Wu system of analysis. Rectal temperatures were obtained preliminary to taking the sample.

The results indicate an average increase of 50% in non-protein-nitrogen, and an 80% increase of uric acid, in the diseased birds. In the chlorides, computed as sodium chloride, a barely significant average increase was noted. The range of blood sugar values was too wide to warrant comparisons. The body temperature of sick specimens averaged 3.5° F. below normal. The results on normal birds are shown in Table I and those for diseased birds in Table II. In the diseased birds there appeared to be a relationship between non-protein-nitrogen, uric acid and body temperature, the figures obtained for these constituents increasing with increase of temperature. The 2 lowest figures for non-protein-nitrogen were obtained in the sickest birds, in one case the value lying below the minimum normal. The values were highest in the birds, that were apparently nearing recovery, as evidenced by their ability to walk or fly.