Effects of castration and a lidocaine-plus-flunixin treatment on growth and indicators of pain, inflammation, and liver function in Korean cattle bull calves

The aim of this study was to determine the effects of castration and a lidocaine-plus-flunixin (LF) treatment on growth and indicators of pain, inflammation, and liver function in Korean cattle bull calves. Forty Korean cattle bull calves (body weight 197.0 ± 2.94 kg and age 6.3 ± 0.09 months) were each assigned to one of four treatments (n = 10 heads/group): no castration with no LF injection (NC-NLF); no castration with LF injection (NC-LF); castration with no LF injection (C-NLF); and castration with LF injection (C-LF). LF treatment included a local anesthetic lidocaine hydrochloride injection (12 mL of 2% in the scrotum) and intravenous injection of a non-steroidal anti-inflammatory drug, flunixin meglumine (2 mg/kg body weight of 50 mg/mL solution), immediately prior to castration. For the NLF groups, a 0.9% NaCl placebo solution was used. Castration was performed surgically using a Newberry knife and a Henderson castrating tool. Blood was collected immediately before castration and at h 0.5, h 6, d 1, d 3, d 7, and d 14 after castration. Feed intake was recorded daily, and body weight was measured on the day prior to the experiment and at d 14 after castration. Castration tended (P = 0.07) to decrease average daily weight gain, but LF treatment did not affect weight gain. Castration increased both circulating cortisol concentrations (P < 0.001) at h 0.5 after castration and substance P (SP) concentrations (P = 0.001) at h 6 after castration. However, the LF treatment did not significantly reduce cortisol and SP concentrations in castrated animals. Castration increased (P < 0.001) circulating haptoglobin (Hp) concentrations on d 1 and d 3 after castration, and LF treatment tended (P = 0.09) to decrease Hp concentrations on d 1 and decreased (P = 0.02) Hp concentrations on d 3. Castration did not affect glutamic oxaloacetic transaminase (GOT) and glutamic pyruvate transaminase (GPT) concentrations. LF treatment increased GOT concentrations at h 6 (P < 0.001), d 1 (P < 0.001), and d 3 (P = 0.003). LF treatment also increased GPT concentrations on d 1 (P = 0.006) and d 3 (P = 0.003). In conclusion, castration of bull calves resulted in time-sequential increases in circulating concentrations of cortisol at h 0.5, SP at h 6, and Hp on d 1. LF treatment did not significantly reduce elevated cortisol and SP, but tended to decrease elevated Hp concentrations in castrated animals. Our study demonstrates that LF treatment is not sufficient for the reduction of the indicators of pain and inflammation in castrated calves, suggesting that additional alleviation methods are required.