Abstract
Knowledge of the normal ultrasound anatomy in the donkey is essential to understand pathological changes and to reach an early diagnosis, considering the "dullness" and stoicism of these animals in pain manifestations. The aims of this study were to document which abdominal viscera could be identified using a transcutaneous ultrasonography technique under field conditions in unsedated, standing donkeys to determine where the different abdominal structures could be easily displayed and to describe any variation that occurred between different donkeys and horses. In this work, the manual technique for performing an ultrasound of the abdominal organs in a donkey is described, including acoustic windows. In addition, several measurements were performed and correlated with the age and weight of the animal to find possible variations. For several of the abdominal viscera, donkeys were found to have similarities with horses, but some differences were found, mostly related to kidney size and the technique for liver visualization. The wall thickness of the colon was confirmed as higher compared to horses, while other intestinal tracts were found to be comparable. A correlation between body weight and organ measurements was only found for the length of both kidneys.