This study aimed to relate embryonic/fetal vesicle diameter (EVD) and crown-rump length (CRL) to gestational age in ewes from the 15th to the 45th day of pregnancy. Nineteen adult Bergamácia ewes with synchronized estrus were mated by the same male. Ultrasonographic evaluations were performed every 24 hours from the 15th to the 30th day after mating and every five days from the 30th to the 45th day using 5.0 and 7.5MHZ linear transducers. Average daily growth of EVD and CRL were 1.40mm and 1.33mm, respectively. The inverse calibration obtained for EVD was: Days = -11 + 50(0.1 + 0.04log EVD)½ with R² = 0.85, and for CRL was: Days = 13.63 + 12.5(- 0.71 + 0.16CRL)½ with R² = 0.93. Both EVD and CRL obtained by ultrasonography are useful measurements that allow the prediction of gestational age in Bergamácia ewes.
Sheep; ultrasonography; pregnancy; embryonic/fetal vesicle; crown-rump
