Glutaraldehyde coagulation test, zinc sulfate turbidity test, and total protein refractometry were adapted for use in detecting failure of passive transfer of colostral immunoglobulins to mule deer fawns (Odocoileus hemionus). The results of all three tests were similar. Serum total protein concentration was directly correlated to gamma globulin concentration and gave the best indication of morbidity and mortality. Thirteen of 13 fawns with serum total protein concentrations of 5 g/dl or less at 1 to 7 days of age developed diarrhea and died before 17 days of age. Only 1 of 14 fawns having a serum protein concentration above this level became sick and died. Seven of 13 fawns that had serum total protein concentrations of 5 g/dl or less, and that had already developed diarrhea, were given 20 ml of plasma per kg body weight. Although this increased their serum gamma globulin concentrations 0.3 g/dl, none survived. Administration of bovine colostrum to one fawn increased its serum gamma globulin concentration suggesting that mule deer fawns are able to absorb gamma globulins from bovine colostrum.