Thermal imaging as a potential tool for identifying piglets at risk

Abstract

Newborn piglets are more susceptible to cold than to heat stress, and cold stress is one of the most significant stressors encountered early in life (Herpin et al., 2002). Piglets usually experience a sudden drop in ambient temperature at birth (range: 15-20 °C), which normally results in a 2 to 4 °C drop in core body temperature (Lossec et al., 1998). The ability to conserve heat is very limited due to the piglets' lack of brown adipose fat, relatively large body surface-to-volume ratio, and sparse hair coat (Herpin et al., 2002). Pig numbers per farm in Australia (APL, 2009-2010) and Europe (Blokhuis et al., 2003) have increased while the ratio of stockmen to animals has severely declined, making the recognition of piglets at risk extremely important. Detection of these animals (visual, clinical or serological examinations) in large operations is challenging and stockmen are often unable to identify all at risk animals at an early stage (Blokhuis et al., 2003). Consequently, opportunities to intervene are limited, resulting in higher mortality rates. Core body temperature is usually measured rectally using a glass-mercury or a digital rectal thermometer. These tools are still invasive, practically challenging for implementation in large populations, and requires extra labour resources. Infrared thermography (IR), on the other hand, is a modern and non-invasive technique for monitoring temperatures and can accurately monitor small changes in temperature. Infrared thermography has been used to detect foot and mouth disease in beef cattle (Rainwater-Lovett et al., 2009), stress in pigs (Schaefer et al., 1989), and bull infertility (Lunstra and Coulter, 1997). The aim of this experiment was to investigate the use of thermal imaging as an early diagnostic tool to identify hypothermic piglets.