Luteal tissue blood flow and side effects of horse-recommended luteolytic doses of dinoprost and cloprostenol in donkeys.
Authors: Magalhaes Humberto B, Dell'Aqua Jose Antonio, Canisso Igor F
Journal: Journal of equine veterinary science
Summary
# Editorial Summary: Luteolytic Agents in Donkeys – Efficacy and Side Effect Profiles When inducing luteolysis in jennies, equine practitioners typically extrapolate dosing recommendations from horse studies, yet donkey reproductive physiology may respond differently to standard prostaglandin protocols. Magalhaes and colleagues conducted a crossover trial in eight donkeys across 16 oestrous cycles, administering horse-recommended doses of dinoprost (5 mg i.m.) and cloprostenol (0.25 mg i.m.) at day 5 post-ovulation whilst monitoring luteal blood flow via Doppler ultrasonography, progesterone concentrations via radioimmunoassay, and clinical side effects over 48 hours. Both agents successfully induced luteolysis with progesterone declining within 30 minutes to 1 hour, though dinoprost provoked a more rapid and pronounced increase in luteal blood flow (peaking at +49% by 3 hours) compared to cloprostenol (+39% by 5 hours). Critically, the two drugs produced markedly different adverse effect profiles: dinoprost caused significantly greater sweating, whilst cloprostenol induced greater abdominal discomfort and diarrhoea. Practitioners can now use these distinct pharmacological signatures to inform individual case selection—dinoprost may suit donkeys with lower pain sensitivity or tolerance for autonomic responses, whereas cloprostenol could be preferred in animals where gastrointestinal upset poses greater clinical concern or welfare risk.
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Practical Takeaways
- •Both dinoprost and cloprostenol at horse-recommended doses effectively induce luteolysis in donkeys, but practitioners should select based on expected side effects: dinoprost for animals where sweating is tolerable, cloprostenol for those where GI disturbance must be minimized
- •Expect different peak luteolytic responses: dinoprost acts faster (3 hours) than cloprostenol (5 hours), which may influence timing of follow-up breeding protocols
- •Monitor jennies closely for 1-8 hours post-injection; both drugs produce measurable side effects that warrant owner communication and potential management adjustments
Key Findings
- •Dinoprost increased luteal blood flow by 49% at 3 hours while cloprostenol peaked at 39% at 5 hours post-administration
- •Both drugs reduced luteal blood flow by 50% at 8 hours, 25% at 12 hours, and 10% at 24 hours
- •Dinoprost induced greater sweating while cloprostenol caused greater abdominal discomfort and diarrhea in treated jennies
- •Progesterone concentrations decreased within 0.5-1 hour for both drugs and continued declining through 48 hours, confirming effective luteolysis