This graph shows the effect local anaesthetic and / or a NSAID has on the plasma cortisol response in the three hours after Burdizzo castration of three week old lambs
Both the local anaesthetic and NSAID were required to effectively reduce the cortisol response, and by inference the pain, following Burdizzo castration of lambs.
The peak plasma cortisol response of 120nmol/l occurred 24 minutes after Burdizzo castration with a secondary peak of 50 and 35 nmol/l occurring between 60 and 132 minutes after treatment. The cortisol peak was reduced to 85 nmol/l by both the local anaesthetic and the NSAID on their own. The local anaesthetic did not appear to have a significant effect on the secondary inflammatory cortisol response. However, the NSAID completely removed the secondary response. The two drugs in combination were more effective, reducing the peak plasma cortisol response to 45 nmol / l, which is close to the mean values measured in handled only lambs (not exceeding 25nmol/l).