Revisiting pain management: Auricular field block analgesia in neonatal dairy calves

The human diamond auricular nerve block was evaluated in 10 clinically healthy, 15-20 days old, neonatal calves weighing 36.05 kg (mean). The animals were randomly allotted to treatment (n=7) and control (n=3) groups. They were restrained in lateral recumbency, 10 min after injecting xylazine HCl (0.05 mg/kg, body wt, i.m.) and bilateral auricular field block was attempted using 10.0 mL, 1% lignocaine HCl or normal saline, in treatment and control animals, respectively. The analgesia was indicated by absence of the behavioural responses to the nociceptive pinpricks at three specific spots on either auricular surface after 10 min, 20 min and 30 min. In the calves of the treatment group, significant difference (P < 0.05) in the analgesia of the two auricular surfaces was recorded at all intervals. The posterior auricular surface showed better analgesia (85.71%, 95.24% and 92.86% pricks) than the anterior surface (4.76%, 4.76% and 2.38% pricks). From this preliminary trial it was concluded that the conventional human auricular field block did not produce satisfactory analgesia in neonatal calves.