Metabolic and Endocrine Insights in Donkeys.
Authors: Mendoza Francisco J, Toribio Ramiro E, Perez-Ecija Alejandro
Journal: Animals : an open access journal from MDPI
Summary
Donkeys are increasingly kept for companionship, therapeutic work, and competition, yet their metabolic and endocrine management remains poorly characterised compared to horses. Mendoza and colleagues reviewed current knowledge of donkey physiology and disease, highlighting that obesity-related disorders—particularly hyperlipemia, metabolic syndrome, and insulin dysregulation—occur frequently in this species and can be life-threatening through multiorgan failure or secondary complications such as chronic laminitis. The authors emphasise that pituitary pars intermedia dysfunction (PPID), a progressive neurodegenerative condition, is also prevalent in donkeys' long lifespan. Whilst baseline resting serum insulin and plasma ACTH measurement form the foundation of diagnostic workup for metabolic and endocrine disease, donkey-specific reference ranges remain poorly defined; consequently, dynamic testing (oral sugar test for insulin dysregulation, thyrotropin-releasing hormone stimulation for PPID) becomes necessary when clinical suspicion is high but baseline values fall within equine reference intervals. Practitioners should recognise that most equine treatment protocols translate to donkeys, though pharmacological evidence beyond pergolide is limited, underlining the need for donkey-specific research to optimise metabolic management and prevent serious morbidity in this growing patient population.
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Practical Takeaways
- •Screen donkeys for metabolic disorders early, especially obese individuals and those with recurrent laminitis, using baseline insulin and ACTH, then dynamic tests if results are borderline
- •Be aware that donkey-specific diagnostic thresholds differ from horses—consult current donkey reference ranges rather than equine cut-off values when interpreting hormone tests
- •Expect PPID prevalence in aged donkeys; monitor for classic signs (hypertrichosis, regional adiposity, laminitis, weight loss) and use appropriate dynamic testing for diagnosis
Key Findings
- •Hyperlipemia, metabolic syndrome, and insulin dysregulation are common metabolic disorders in donkeys with high mortality rates from multiorgan dysfunction or chronic laminitis
- •Resting serum insulin and plasma ACTH concentrations are primary diagnostic markers for insulin dysregulation and PPID, but donkey-specific reference ranges need establishment
- •Dynamic testing (oral sugar test or thyrotropin-releasing hormone stimulation) is recommended when clinical signs are present but hormone concentrations fall in non-diagnostic ranges
- •Most equine treatment protocols apply to donkeys, but pharmacological studies for most drugs are lacking except for pergolide