This study investigated the temperature of pigs’ blood as it flowed from the sticking wound at exsanguination using infra-red thermometry and how it might reflect changes in core body temperature. A total of 417 pigs were monitored over a three-day period, which included a subset of 206 pigs for which additional information concerning transport conditions and ambient temperature was also known. The range of blood temperatures recorded was large (35.6-43.2°C) with a significant number of the animals found to have blood temperatures above the pigs’ normal temperature (39 ± l°C). Within the subset of pigs, average blood temperature of all the pigs in a pen at slaughter appeared to be related to pen temperatures and position on the lorry and was sensitive enough to detect changes in environmental ambient conditions.