Non-Contact Evaluation of Pigs’ Body Temperature Incorporating Environmental Factors

Abstract

Internal body temperature is the gold standard for the fever of pigs, however non-contact infrared imaging technology (IRT) can only measure the skin temperature of regions of interest (ROI). Therefore, using IRT to detect the internal body temperature should be based on a correlation model between the ROI temperature and the internal temperature. When heat exchange between the ROI and the surroundings makes the ROI temperature more correlated with the environment, merely depending on the ROI to predict the internal temperature is unreliable. To ensure a high prediction accuracy, this paper investigated the influence of air temperature and humidity on ROI temperature, then built a prediction model incorporating them. The animal test includes 18 swine. IRT was employed to collect the temperatures of the backside, eye, vulva, and ear root ROIs; meanwhile, the air temperature and humidity were recorded. Body temperature prediction models incorporating environmental factors and the ROI temperature were constructed based on Back Propagate Neural Net (BPNN), Random Forest (RF), and Support Vector Regression (SVR). All three models yielded better results regarding the maximum error, minimum error, and mean square error (MSE) when the environmental factors were considered. When environmental factors were incorporated, SVR produced the best outcome, with the maximum error at 0.478 °C, the minimum error at 0.124 °C, and the MSE at 0.159 °C. The result demonstrated the accuracy and applicability of SVR as a prediction model of pigs′ internal body temperature.

Dynamic Variations in Infrared Skin Temperature of Weaned Pigs Experimentally Inoculated with the African Swine Fever Virus: A Pilot Study

“…The results also confirmed that the T sk from ASFV-infected pigs was distinct from T core , which was coincident with previous studies [ 1 , 13 , 14 , 16 , 26 ]. Previous studies have also revealed the relationship between T sk and T core in pigs, indicating that they differ depending on the age and breed of pigs, ambient temperature, and region of body measured [ 13 , 16 ].…”

“…Fever or internal temperature ( T core ) in pigs is commonly assessed by measuring rectal temperature with a mercurial thermometer. However, this method is invasive and requires manual handling of animals, which might increase the risk of spreading infectious pathogens within farms [ 1 , 2 ]. Infrared thermography (IRT) is a technique that creates a visible image from the invisible infrared radiation emitted by an object [ 3 ].…”

“…Moreover, the main control strategies during ASF outbreaks are livestock culling and quarantine, as there is no vaccine available. Since high fever is one of the most important clinical signs of ASF infection [ 12 ], the T sk measurement method could be practically applied for surveillance of ASF in endemic/affected areas [ 1 ].…”

“…In order to utilize IRT as a disease diagnostic tool, it is necessary to evaluate the correlation between T sk and T core of the infected pigs. However, most studies on IRT have been limited to healthy pigs [ 1 , 13 , 14 , 15 ], and only a few studies have addressed the T sk in the case of porcine respiratory disease [ 5 , 6 ]. Therefore, this study investigates the dynamic comparison between T sk recorded from thermal infrared (TIR) images of the ASFV-infected pig herd and their T core .…”

Clinical Applications and Factors Involved in Validating Thermal Windows Used in Infrared Thermography in Cattle and River Buffalo to Assess Health and Productivity

“…In this region, in both the rat and the bovine tail, large straight vessels aid to the thermoregulation [ 20 ], and validating thermal windows requires high sensitivity and specificity to predict physiological states accurately. Although this has been achieved in several species [ 44 ], the reliability of this approach is limited by several conditions, such as the presence or absence of hair (glabrous skin), fur thickness, skin thickness, and fur color, all of which can alter heat gain or loss [ 45 ]. In addition, these characteristics establish differences among species, such as those between dogs and rats.…”