Pregnancy Detection in Bighorn Sheep (Ovis Canadensis) Using a Fecal-based Enzyme Immunoassay

Dori L Borjesson, Walter M Boyce, Ian Gardner, James DeForge, Bill Lasley

Research output: Contribution to journalArticlepeer-review

18 Scopus citations


We developed and validated an enzyme immunoassay for immunoreactive pregnanediol-3-glucuronide (iPdG) in feces to monitor reproductive status in desert and Rocky Mountain bighorn sheep (Ovis canadensis). Fecal iPdG concentrations were strongly correlated (r = 0.71) with serum progesterone concentrations in paired fecal and blood samples collected from 34 free-ranging desert bighorn sheep. In bimonthly fecal samples collected from 12 captive ewes, fecal iPdG profiles were similar between desert and Rocky Mountain bighorn sheep and we selected a pregnancy detection cutoff value of iPdG ≥1.8 ng/mg feces. Fecal iPdG concentrations always exceeded this cutoff value when samples were collected from about day 60 of pregnancy to a few days before parturition, but values <1.8 ng/mg (false negatives) were common for samples collected during the first 60 days of gestation. Although we tested a small number of known pregnant and non-pregnant ewes, the accuracy of the assay was 100% when two samples, collected 2 wk apart, were evaluated for any given ewe. Based on these data, this direct enzyme immunoassay for fecal progesterone metabolites has promise as a diagnostic tool to monitor hormone excretion and pregnancy in a free-ranging ungulate species.

Original languageEnglish (US)
Pages (from-to)67-74
Number of pages8
JournalJournal of Wildlife Diseases
Issue number1
StatePublished - Jan 1996


  • Bighorn sheep
  • Fecal steroids
  • Immunoassay
  • Pregnancy
  • Progesterone
  • Reproduction

ASJC Scopus subject areas

  • veterinary(all)


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