Submitted to: Biosystems Engineering
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/28/2012
Publication Date: 2/9/2013
Citation: Brown Brandl, T.M., Eigenberg, R.A., Purswell, J.L. 2013. Using thermal imaging as a method of investigating thermal thresholds in finishing pigs. Biosystems Engineering. 114:327-333.
Interpretive Summary: The metabolism of modern swine has increased in recent years as swine have become leaner. With this change in metabolism, the question of “what facility temperature is appropriate for growing swine?” has arisen. A study was completed to evaluate the use of a thermal imaging camera to determine the thermal tolerance of pigs. A study was completed using 20 individual pigs, and 16 pens of pigs. Pigs were photographed using a thermal imaging camera at seven distinct temperatures ranging from 21.3 to 36.6°C. It was determined that thermal images can be used to evaluate the thermal needs of pigs. The ideal temperature could not be determined by this study; however, it was found that grow-finish pigs could benefit from supplemental cooling above 21 - 23°C. The study needs to be expanded to include lower temperatures and additional ages/weights of pigs.
Technical Abstract: Heat production from modern pigs has been determined to be significantly higher than previously defined in the standards. This increase in heat production changes the thermal needs of modern growing swine. A study was designed to evaluate heat tolerance of growing swine based on changes in thermal images captured at different temperatures. Thermal images were taken of one hundred sixty group-penned pigs (26.9 – 62.2 kg) and twenty individual pigs (31.1 – 57.2 kg) on seven selected days at seven different temperatures (21.3°C– 36.6°C). The thermal images were analyzed to determine either average temperature (individual pigs) or high and low temperatures (group penned pigs). The surface temperatures were significantly affected by ambient temperature and response equations were developed. A breakpoint analysis revealed a threshold, thought to equate to the top of the thermal neutral zone, ranging between 17.4°C and 23.2°C. It was concluded that thermal images can be successfully used to evaluate the thermal needs of pigs and that the experiment needs to be expanded to include lower temperatures to ensure this threshold is correct.