Factors affecting the accuracy of pregnancy scanning in ewes

The objective was to evaluate the accuracy of pregnancy scanning by transabdominal ultrasonography and affecting factors. Altogether 44,783 ewes were registered (2008–2010), 39,724 diagnosed as pregnant and subsequently lambed. The ewes, 0.5–14 years old, were divided into 4 age and 6 breed groups and analysed. The accuracy (per cent; number of scanned fetuses/number of born lambs) decreased with increasing number of fetuses (P