Accuracy of radiographic fetal count in ewes

  • Camille Ogdon Carlson College of Veterinary Medicine, Oregon State University, Corvallis, OR, USA
  • Charles Estill Carlson College of Veterinary Medicine, Oregon State University, Corvallis, OR, USA
  • Kelly Van Scoyk Carlson College of Veterinary Medicine, Oregon State University, Corvallis, OR, USA
  • Lauren Newsom Carlson College of Veterinary Medicine, Oregon State University, Corvallis, OR, USA
Keywords: Sheep, pregnancy, radiograph, ultrasound, abdominal computed tomography, fetal count, litter size, pregnant ewe, fetal skeleton


Accurate fetal count is important for farm animal species as the number of fetuses can affect management decisions in both research and production settings. Documented methods of pregnancy diagnosis include radiography, progesterone assays, transrectal palpation, and transrectal and transabdominal ultrasonography; however, there is variability in fetal count accuracy with each of these methods. Abdominal radiography evaluation in 13 pregnant ewes among observers of various skill levels was compared retrospectively with the known number of fetuses determined using computed tomography. Overall accuracy using abdominal radiography across skill levels for determining fetal counts correctly was 79%. Accuracy decreased as the number of fetuses increased, with accuracies for singleton, twin, and triplet pregnancies being 92, 72, and 50%, respectively. Additionally, observer experience was inversely related to radiographic fetal count accuracy.


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How to Cite
Ogdon C., Estill C., Van Scoyk K., & Newsom L. (2023). Accuracy of radiographic fetal count in ewes. Clinical Theriogenology, 15.
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