Investigating the effect of local anaesthetic cream on the behavioural response to intravenous cannulation of calves.

OBJECTIVE

To evaluate the behavioural response of calves to intravenous (IV) cannulation following application of local anaesthetic cream or a placebo, with a focus on the efficacy of 2 or 5 minute exposure periods.

STUDY

DESIGN

Prospective, randomised, blinded, placebo-controlled clinical trial.

ANIMALS: A total of 60 Holstein calves enrolled as part of a scheduled disbudding procedure.

METHODS

Holstein calves were randomly assigned to four groups: local anaesthetic [eutectic mixture of local anaesthetics (EMLA)] or placebo with 2 or 5 minute exposure (15 calves per group). After treatment, an IV catheter was placed in a jugular vein and behavioural responses to catheter placement were scored on a 0-3 scale, with a higher value indicating a greater response. Reaction scores were analysed using Mann-Whitney U tests, with statistical significance set at p < 0.05. Cream application sites were evaluated 15 minutes post-procedure for any adverse effects.

RESULTS

No adverse effects or dermal toxicity were observed. Behavioural response scores did not differ significantly between the EMLA 2 group [median (range): 1 (0-3)] and the Placebo 2 group [1 (0-3); p = 0.566]. However, a significant difference was observed between the EMLA 5 group [0 (0-2)] and the Placebo 5 group [1 (0-3); p = 0.010].

CONCLUSIONS AND CLINICAL RELEVANCE: This study demonstrates that a 5 minute exposure to EMLA cream effectively reduced behavioural reactions in calves during IV cannulation. Based on these findings, a 5 minute exposure period may be recommended to improve the welfare of calves undergoing IV cannulation.