Post-operative pain behaviour associated with surgical castration in donkeys (Equus asinus).
Authors: de Oliveira Maria Gláucia Carlos, Luna Stelio P L, Nunes Talyta Lins, Firmino Paulo R, de Lima Amara Gyane A, Ferreira Josiel, Trindade Pedro H E, Júnior Raimundo A B, de Paula Valéria Veras
Journal: Equine veterinary journal
Summary
# Editorial Summary: Pain Behaviour Following Surgical Castration in Donkeys Donkeys are notoriously stoic patients, making pain assessment difficult in clinical practice; this prospective study examined specific behavioural changes in 40 donkeys before and after surgical castration to establish reliable pain indicators. Researchers recorded four 30-minute video observations at baseline (M0), 3.5–4 hours post-recovery (M1), 5.5–6 hours post-recovery with analgesia administered (M2), and 23.5–24 hours post-recovery (M3), whilst controlling for environmental confounders such as faeces presence and insect activity. Pelvic limb lifting emerged as the only behaviour specifically associated with post-operative pain, increasing significantly at M1 compared to baseline; crucially, analgesia (flunixin meglumine 1.1 mg/kg, dipyrone 10 mg/kg and morphine 0.2 mg/kg) successfully reversed this behaviour alongside restoring feeding and water intake whilst reducing ear movements, head shaking and head turning. Head, ear and tail movements proved unreliable pain indicators as they increased substantially in response to a soiled stall environment, highlighting that environmental cleanliness and insect presence are critical confounding variables when assessing pain in donkeys. Clinicians should focus on pelvic limb lifting as a specific pain marker post-castration and recognise that other traditional pain behaviours in donkeys may reflect environmental irritation rather than surgical pain.
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Practical Takeaways
- •When assessing pain in donkeys post-castration, focus on pelvic limb lifting as the most reliable pain indicator; be cautious interpreting ear/head/tail movements as these are easily confounded by environmental factors
- •Keep donkey stalls clean and manage insects carefully during post-operative monitoring to avoid misinterpreting behavioral responses as pain-related
- •Multi-modal analgesia (NSAID + analgesic + opioid) effectively manages post-castration pain in donkeys, evidenced by restoration of normal feeding and water intake within 5-6 hours post-recovery
Key Findings
- •Pelvic limb lifting was the only specific pain indicator after castration, with increased frequency at M1 compared to baseline (P=0.003)
- •After analgesia administration at M2, ear movements decreased from median 44 to 16 (P<0.001), head shaking from 7 to 1 (P<0.001), and feeding increased from 0 to 29 observations (P<0.001)
- •Tail, head and ear movements are non-specific responses confounded by dirty stall conditions and insect presence, limiting their use as pain indicators in donkeys
- •Analgesia with flunixin meglumine, dipyrone and morphine successfully restored appetite and water intake while reducing pain-related behaviors