Accuracy of radiographic fetal count in ewes

Abstract

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.