Comparison of Flunixin Meglumine, Meloxicam and Ketoprofen on Mild Visceral Post-Operative Pain in Horses

Abstract

The analgesic efficacy of meloxicam and ketoprofen against equine visceral pain is unclear. The aim of this study was to compare the analgesic efficacy of meloxicam (M) and ketoprofen (K) to flunixin meglumine (F) following inguinal castration. Horses undergoing inguinal castration under general anesthesia were randomly assigned F (1.1 mg/kg), M (0.6 mg/kg) or K (2.2 mg/kg) intravenously two hours pre-operatively and 24 h later. A pain score (out of 31) was recorded blindly by a senior clinician and veterinary student before NSAIDs administration (T0), and after the first (T1) and second (T2) administrations, using a modified post-abdominal surgery pain assessment scale (PASPAS). Pain was classified as mild (score ≤ 7), moderate (score = 8–14) or severe (score > 14). Thirty horses (12 F, 10 M, 8 K) aged 6.2 ± 4.9 years, mostly warmbloods, were included. Horse welfare was not compromised regardless of the drug assigned. There was no statistically significant effect of NSAIDs on pain score. Mean pain scores were significantly higher at T1 than T0 for each NSAID (F: 5.08 ± 2.50 vs. 1.58 ± 1.38 (p < 0.001); M: 4.60 ± 2.32 vs. 1.10 ± 1.20 (p < 0.001); K: 5.25 ± 1.39 vs. 1.50 ± 1.51 (p < 0.0001)) and lower at T2 than T1 for F (2.92 ± 2.423 vs. 5.08 ± 2.50 (p < 0.001)) and M (2.90 ± 1.37 vs. 4.60 ± 2.32 (p < 0.0325)). At T1, senior pain scores were significantly different than for junior (5.56 ± 0.54 vs. 3.22 ± 0.62, p = 0.005). This study indicates that meloxicam and ketoprofen provide a similar level of analgesia to flunixin meglumine for the management of mild visceral pain in horses. PASPAS is not reliable for junior evaluators.

Perioperative pain management protocols of veterinarians in the United States for horses undergoing routine orchiectomy (castration)

“…Butorphanol and xylazine are estimated to provide analgesia for a maximum of 3 to 4 hours or 60 minutes, respectively, after intravenous administration. (Sanchez and Robertson, 2014) It is impossible to know exactly how long a horse may be painful after routine castration, but studies have reported behavioral evidence of pain for more than 8 hours (Dalla Costa et al, 2014;Lemonnier et al, 2022;Love et al, 2013), suggesting that relying only on drugs administered at the time of surgery may be inadequate for pain control.…”

“…Several equine pain behavior instruments have been used to evaluate pain experienced by horses after routine castration procedures with the general conclusion that there are differences in behavior of horses after castration that may be modified or ameliorated with administration of analgesic medications. (Dalla Costa et al, 2021;Dalla Costa et al, 2014;Lawson et al, 2020;Lemonnier et al, 2022;Lencioni et al, 2021;Sanz et al, 2009;Taffarel et al, 2015;Trindade et al, 2021;van Loon et al, 2010) In a 2020 survey of equine veterinarians in the United States (US), respondents were asked to rate the degree of pain experienced by a yearling colt 24 hours after a routine castration was performed, assuming no analgesia was provided after the procedure, using a numerical rating scale of 0 (no pain at all) to 10 (worst possible pain). (Sellon, Sanz, Kopper, et al, 2022) Responses ranged from 1 to 10 with a median score of 5 and interquartile range of 4 to 7.…”

Perioperative pain management protocols of veterinarians in the United States for horses undergoing routine orchiectomy (castration)

“…Butorphanol and xylazine are estimated to provide analgesia for a maximum of 3–4 h or 60 min, respectively, after intravenous administration (Sanchez & Robertson, 2014). It is impossible to know how long a horse may be painful after routine castration, but studies have reported behavioural evidence of pain for more than 8 h (Dalla Costa et al, 2014; Lemonnier et al, 2022; Love et al, 2013), suggesting that relying only on drugs administered at the time of surgery may be inadequate for pain control.…”

“…Several equine pain behaviour instruments have been used to evaluate pain experienced by horses after routine castration procedures with the general conclusion that there are differences in behaviour of horses after castration that may be modified or ameliorated with administration of analgesic medications (Dalla Costa et al, 2014, 2021; Lawson et al, 2020; Lemonnier et al, 2022; Lencioni et al, 2021; Sanz et al, 2009; Taffarel et al, 2015; Trindade et al, 2021; van Loon et al, 2010). In a 2020 survey of equine veterinarians in the United States (US), respondents were asked to rate the degree of pain experienced by a yearling colt 24 hours after a routine castration was performed, assuming no analgesia was provided after the procedure, using a numerical rating scale of 0 (no pain at all) to 10 (worst possible pain) (Sellon et al, 2022).…”