Challenges of thermal nociceptive threshold testing in the donkey

Abstract

Objective To evaluate a thermal nociceptive threshold (TNT) testing device in the donkey, and the influence of potential confounding factors on TNTs. Animals Two groups (Group 1 and Group 2) of eight castrated male donkeys aged 4–9 years, weighing 105–170 kg. Methods TNTs were measured by heating a thermal probe on skin until an end-point behaviour (threshold temperature) or a cut-out temperature (51 °C) was reached. The withers and the dorsal aspect of the distal limb were used as sites for TNT testing. The effects on TNT of different confounding factors: the limb tested; rate of heating; and ambient temperature were evaluated. Data were analyzed using general linear models, and Mann-Whit..