Acute cortisol responses of lambs to ring castration and docking after theinjection of lignocaine into the scrotal neck or testes at the time of ring application

Objective To test whether injecting lignocaine into the scrotal neck 5 to 1 0 s before or into both testes immediately after ring castration and dockin g would significantly reduce the plasma cortisol response to castration and docking. Design A physiological study with controls. Procedure Lambs were given one of six treatments: control handling, injecti on of lignocaine into scrotal neck, injection of lignocaine into both teste s, ring castration and docking, ring castration and docking after lignocain e was injected into the scrotal neck, and ring castration and docking befor e lignocaine was injected into both testes. Blood samples were taken before and regularly after treatment and analysed for plasma cortisol concentrati ons. Results The plasma cortisol concentrations of lambs castrated and docked af ter lignocaine had been injected into the scrotal neck were significantly l ower between 20 and 60 min after treatment than in lambs castrated and dock ed without local anaesthesia. Injecting lignocaine into the testes after ri ng application did not significantly reduce the cortisol response to ring c astration and docking. Conclusions Lignocaine injected into the scrotal neck 5 to 10 s before ring castration will reduce the cortisol response and by inference the pain ass ociated with ring castration.