Relationship between ultrasound subcutaneous fat depth, body condition score and body subcutaneous fat distribution in Miranda breed jennets

Abstract

In northeast Portugal, donkeys usually face seasonal food shortage and often their basic requirements are not properly met. Body condition score (BCS) may be used to assess a donkey's welfare and nutritional status, but the procedure is highly subjective. For several domestic species the relationships between the ultrasound subcutaneous fat depth, the body condition score and the body subcutaneous fat distribution have already been established. Interspecies differences on the most relevant sites for ultrasound collection of data have been demonstrated, in particular between equids and ruminants. In donkeys, no available information exists on the relationship between ultrasonographic fat depth and its pattern of deposition and the BCS, so a preliminary study was developed using 16 adult jennets of the Asinina de Miranda breed, in a total of 33 examinations for BCS and real time ultrasound (RTU). RTU images were acquired to determine the subcutaneous fat depth (SF), measured at the neck, loin, rump and tail-head, and tissue depth (TD) measured at ribs. SF distribution was analysed and the correlations between BCS and RTU measurements were assessed. The largest variations in SF deposition were found along the thoracolumbar axis, although RTU measurements parallel better the BCS variations when taken at the other sites, in particular those taken over the ribs. Significant correlations were found between BCS and RTU measurements (SF and TD) for all sites except for the neck. Our results suggest that RTU is a potentially valuable tool to monitor body condition and body subcutaneous fat distribution in jennets, with the advantage of being a non-invasive, accurate and easily implemented technique.