Application of infrared ocular thermography for welfare and meat quality assessment of slaughter pigs

Abstract

Infrared ocular thermography is a non-invasive tool used in the pork industry to quickly assess animal stress and its impact on meat quality. The aim of this study was to investigate the association between the infrared ocular temperature and blood indicators and meat quality traits in slaughter pigs. The study was conducted on 60 market-weight pigs (average live weight of about 110 kg and 6 months old) of the same genetics. Infrared ocular thermography images were obtained immediately after stunning. Blood samples were collected at exsanguination to determine glucose level and oxidative stress biomarkers, including advanced oxidation protein products (AOPP), ceruloplasmin, reduced glutathione (GSH), total antioxidant capacity (TAC), total oxidant status (TOS) and the oxidative stress index (OSI). Meat quality traits, including pH, temperature, colour (L*, a* and b* values), water-holding capacity (drip, thawing and cooking loss) and pork quality classes, were measured. Pigs with infrared ocular temperatures above 32 ºC had higher plasma concentrations of GSH and TOS. Pork obtained from the same group of pigs had higher cooking loss and a* value, along with tendency towards higher L* and b* values. Furthermore, pigs with infrared ocular temperatures above 32 ºC had higher tendency towards development of pale, firm and nonexudative meat. These results indicate that elevated ocular temperature is linked to oxidative stress and changes in meat quality, suggesting a connection between pre-slaughter stress and post-mortem meat characteristics. In conclusion, infrared ocular thermography has potential as rapid, non-invasive tool for assessing pig welfare and predicting pork quality