Measurement of IgG Concentration in Ovine Fetal Fluids: A Useful Diagnostic Test

The Veterinary Diagnostic Laboratory at Oregon State University received 172 aborted ovine fetuses during the 1985-1987 lambing seasons; from 120 of these, body fluids were evaluated for levels. Fifty-two (43%) of the fetal fluids had immunoglobulin G (IgG) levels greater than 15 mg/dl. Forty-five (87%) of the fluids with elevated levels were confirmed or presumed toxoplasma or Chlamydia abortions. A mean fetal fluid concentration of 111.5 ± 78 mg/dl was found for the 26 toxoplasma abortions; for the 19 Chlamydia abortions, a mean concentration of 109 ± 91 mg/dl was found. Antibody titers equal to or greater than 1:40 against Toxoplasma gondii were detected in 23 fetal fluids. Fetal fluid concentration less than 15 mg/dl was found to be associated with bacterial organisms (i.e., Campylobacter sp.) as the confirmed or presumed cause of abortion. These results suggest that measurement of fetal fluid concentration is a useful, supportive diagnostic test in determining the cause of ovine abortion, and should be included as a routine laboratory procedure for ovine abortion diagnosis. Ovine abortion represents a significant economic loss. 2,8,12,19 The major causes of ovine abortion recog- nized in the United States are Campylobacter sp., Chla- mydia psittaci, Toxoplasma gondii, and a variety of miscellaneous organisms. lo Thirty to forty percent of these cases are not diagnosed when veterinary diag- nostic laboratories receive optimum fetal specimens (fetus, placenta, and maternal serum samples). 8