Evaluating the efficacy of a topical anaesthetic formulation and ketoprofen, alone and in combination, on the pain sensitivity of dehorning wounds in Holstein-Friesian calves

Abstract

The aim of this study was to investigate the effect of a topically applied local anaesthetic and the non-steroidal anti-inflammatory drug ketoprofen, alone and in combination, on the pain sensitivity response of calves to dehorning (mean age 2.2 months). Calves were randomly allocated and blocked by age to one of four groups. Groups were: scoop dehorning (D, n = 8), scoop dehorning + i.m. administration of 3 mg/kg ketoprofen (DK, n = 8), scoop dehorning + application of topical anaesthetic (DTA, n = 7) and scoop dehorning + application of topical anaesthetic and i.m. administration of ketoprofen (DKTA, n = 7). A pressure algometer was used to determine the mechanical nociceptive threshold (MNT), being the pressure (kg/f) at which calves withdrew from the stimulus. Measurements were taken before dehorning and at 1 min, 1, 2, 5 and 24 h post-dehorning at both the cut skin edge of the wound and the peri-wound area. The effect of treatment changed over time (P < 0.001). MNT was highest before treatment (MNT = 5.03 kg/f) and tended to decrease over time (MNT = 1.16 kg/f 24 h post-treatment). Overall, D calves exhibited the lowest MNT with an average of 1.77 kg/f. DTA calves had the highest MNT (3.89 kg/f), followed closely by DKTA calves (3.24 kg/f). DK calves exhibited an intermediate MNT of 2.61 kg/f. MNT of the cut skin edge was generally lower than that of the peri-wound area (2.01 vs 3.81 kg/f, respectively, P = 0.02).The topical anaesthetic formulation significantly reduced the pain sensitivity of dehorning wounds. There was no observed enhanced analgesic effect with addition of ketoprofen. The cut skin edge was more sensitive to pressure than the peri-wound area.