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.

The Effect of Topical Anaesthesia on the Cortisol Responses of Calves Undergoing Dehorning

“…Scoop dehorning in younger calves typically creates bony wounds of small surface area, with haemorrhage, which may limit the quantity of TA absorption. Haemorrhage reduces the ability of the TA to adhere and remain on the wound and has been observed previously [23]. The lack of epithelial or mucosal tissue on small bony dehorning wounds means there is minimal surface area for effective TA absorption, with most nociceptors likely located in the wound edges.…”

“…Topical local anaesthetics are applied to the skin surface (less absorption) or directly onto the mucosal tissue or open wound to induce rapid and lasting local anaesthesia [20,21]. We have previously reported on a topical anaesthetic wound dressing formulation reducing short-term pain sensitivity and increasing mechanical nociceptive thresholds following scoop dehorning in calves [22,23]. This multipurpose formulation contains lignocaine and bupivacaine for local anaesthesia, cetrimide for antisepsis, and aluminium chlorohydrate for astringency of the wound (modified from Tri-Solfen ® ; Bayer Animal Health, Pymble, NSW, Australia).…”

“…The assessment of pain and the efficacy of analgesics can be improved by using a combination of behavioural and endocrine measures [24]. Our previous research has used sensory testing and algometry as pain indicators for the assessment of TA efficacy [22,23]. The activity of the hypothalamic-pituitary-adrenocortical (HPA) system has been extensively measured to gauge the distress of dehorning and the effectiveness of analgesics [9,10,25,26].…”

Effect of Topically Applied Anaesthetic Formulation on the Sensitivity of Scoop Dehorning Wounds in Calves

“…Previous studies have demonstrated the efficacy of a topical anaesthetic formulation (Tri-Solfen®, Bayer Animal Health, Pymble NSW Australia) for use during mulesing [ 14 ], tail docking and surgical castration [ 15 ] in lambs and surgical castration in beef calves [ 16 ]. Preliminary studies have shown that modified formulations of Tri-Solfen® applied to dairy calves during scoop dehorning significantly reduced the sensitivity of wounds up to 1.5 h [ 17 ] and 5 h [ 18 ] following the procedure.…”

“…The overall aim of the previous studies [ 17 , 18 ] and the current study, are to investigate options for providing pain relief to calves undergoing scoop dehorning that are both effective and practical to use on-farm.…”