023 Effect of subcutaneous meloxicam on indicators of acute pain and distress after castration and branding in 2-month-old beef calves

Abstract

Routine management practices such as vaccination, ear tagging, castration, and branding are procedures commonly done on the same day. The aim of this study was to assess the efficacy of a single dose of subcutaneous meloxicam (Metacam 0.5 mg/kg BW) at mitigating acute pain caused by knife castration or the combination of knife castration and hot-iron branding. Seventy-two 2-mo-old Angus bull calves were randomly assigned to a 3 × 2 factorial design: control (CON), knife (K), and knife and branding (KB) without meloxicam and control, knife (KM), and knife and branding (KBM) with meloxicam. Samples were collected on d −1; immediately before castration (T0); at 60, 90, 120, and 180 min after castration; and 1, 2, 3, and 7 d after castration to determine salivary cortisol (SC), substance P (SP), haptoglobin (HP), stride length, and frequency of tail flicking (TF), foot stamping (FS), and head turning (HT) behaviors. A castration × medication × time interaction was observed for HP (P = 0.05) and FS (P = 0.02), where KBM calves had greater HP concentrations than KB calves at T0, whereas KB calves had greater HP concentrations on d 1, 2, 3, and 7 and greater FS frequencies than the KBM group on d 1 and 2. The K calves had greater HP concentrations on d 1 and 2 compared with KM calves. A castration × time interaction was observed for SC (P < 0.01) and TF (P < 0.01). The K and KB calves had greater SC concentrations compared with CON calves 60 min after castration, whereas KB calves had greater concentrations than K calves and both KB and K calves had greater concentrations compared with CON calves 90, 120, and 180 min after castration. The KB and K calves had greater TF frequencies on d 1 and 3 compared with CON calves, whereas KB calves had greater TF than K calves and both groups compared with CON calves on d 2. A castration × medication interaction (P = 0.01) was observed for HT, where K calves were found to have greater HT frequencies than KM calves. No treatment or interaction effects were observed for SP. Overall, a single subcutaneous dose of meloxicam administered immediately prior to the procedures conducted was effective at mitigating physiological (HP and SC) and behavioral (TF, FS, and HT) indicators of pain and distress in calves that were castrated and castrated and branded.