Assessing the efficacy of eutectic mixture of local anesthesia cream and vapocoolant spray in mitigating the pain associated with ear-tagging in pre-weaned calves

This study evaluated the efficacy of a eutectic mixture of local anesthetics (EMLA) cream and vapocoolant spray (VS) in preventing pain in calves following ear-tagging. Thirty-four calves were randomly assigned to three groups: no anesthesia control (CON, n=11), EMLA applied 60 minutes prior (EMLA, n=11), and five-second VS application immediately prior (VS, n=12). Pain pressure threshold (PPT) was measured at 18±1 days of age, with the left ear of the CON group serving as the sham group (Sham, n=11), followed by ear-tagging at 21±1 days. Post-tagging assessments included pain-related behaviors, serum cortisol levels, heart rate, and wound scores. The PPT values were higher in the EMLA and VS groups than in the CON group (P < 0.001), confirming their anesthetic efficacy. The frequencies of head shaking and leg movement were lower in the Sham and EMLA groups compared to the CON group at 0–5 minutes post-tagging (P < 0.01). Similarly, tail flicking and leg movement frequencies were significantly lower in the Sham and VS groups than in the CON group. Back arching occurred in 100% of calves in the CON and VS groups but only 9.1% of EMLA-treated calves. Wound healing was similar across groups, with ≥50% of tagged calves scoring 1. No significant differences in heart rate or serum cortisol levels were observed, suggesting their limited reliability as pain indicators. In conclusion, both EMLA cream and VS effectively alleviated pain after ear-tagging, with EMLA providing superior analgesia. Integrating local anesthetics into routine ear-tagging can improve calf welfare.