Serum Biochemistry Parameters of the Endangered Miranda's Donkey Breed: Reference Intervals and the Influence of Gender and Age

Miranda's donkey is an endangered, autochthone breed from Northern Portugal. Understanding the physiological and pathological conditions of Miranda's donkey is crucial for the conservation of the breed. Our study aimed to establish reference intervals (RIs) for blood biochemistry parameters and to evaluate the influence of gender and age on these parameters. Blood samples from 75 clinically healthy animals were analyzed for 21 blood biochemistry parameters using Respons^® 920 and Start^® 4-Diagnostica-Stago. RIs were calculated according to the ASVCP guidelines, utilizing Reference Advisor software V. 2.1 and the statistical program SPSS version 29 to analyze the effects of gender and age. Significant gender-related differences (p < 0.05) were observed in cholesterol, chlorine, creatinine (CREA), glucose (GLU), sodium, and triglycerides (with higher values in females) and in aspartate aminotransferase, creatine phosphokinase (CK), gamma-glutamyl transferase, potassium, magnesium (Mg), and urea (with higher values in males). Age-related differences (p < 0.05) were noted for alkaline phosphatase, CK, fibrinogen, GLU, and phosphorus (higher in young animals) and for globulin, Mg, and total protein (higher in adults). The RIs described here are invaluable for assessing and monitoring the health status of individual animals and herds. Our study highlights the importance of considering gender and age in the interpretation of biochemical parameters, providing critical insights for the conservation and management of this endangered breed.