Urine sediment characterisation in physically healthy adult jennies (Equus asinus). A cross-sectional study

Urinalysis is a valuable, non-invasive method for evaluating renal function, yet data on donkey urinary parameters remain scarce. This study characterised urinary sediment in fifty-four healthy adult jennies, established urine specific gravity (USG) reference intervals, and proposed a preliminary semi-quantitative sediment grading scale. Urine samples were collected via catheterisation and analysed using refractometry, dipstick testing, and microscopy. The median USG was 1.048 (IQR: 1.040-1.055) with a pH of 7.6 (IQR: 7.2-8.0). Leukocytes and glucose were absent; erythrocytes were found in one sample. Calcium carbonate crystals were present in all samples, followed by calcium oxalate monohydrate (74.07%), mucus filaments (66.67%), and epithelial cells (57.41%). Granular casts were observed in 27.77% and hyaline casts in 7.41% of samples. Healthy jennies show USG values similar to horses. Urinary sediment had abundant calcium carbonate and notable calcium oxalate crystals. These findings establish baseline sediment profiles and support the future validation of a grading scale for sediment evaluation.