Application of infrared thermography to assess the effect of different types of environmental enrichment on the ocular, auricular pavilion and nose area temperatures of weaned piglets

Abstract

The objective of this study was to evaluate through the infrared thermography the surface temperature of the lacrimal caruncle (ocular), auricular pavilion and nose area of weaned piglets in relation to different types of environmental enrichment (EE). A total of 64 weaned piglets were monitored. The piglets were housed under two distinct conditions: a condition without disruption of the social order (SO), and a condition in which the social order was disrupted (DSO). After defining these two conditions, four different EE treatments were evaluated: control (C), suspended ropes (SR), aromatized bottles (AB), and pet toys and balls (PTB). Thermographic images of the lacrimal caruncle, auricular pavilion and nose area of each piglet were taken at 30 and 90 min, and then at 24, 48, 72, 96 and 120 h post-weaning. The piglets housed under the SO condition with no type of EE (Control) maintained lower temperature levels in the lacrimal caruncle (P < 0.05) through the first 48 h post-weaning; 24 and 48 h post-weaning, the piglets housed under the DSO condition with EE in the form of PTB presented the highest temperature in all three regions (P < 0.05); 96 and 120 h, the piglets under the DSO condition with no type of EE (Control) had the highest temperature (P < 0.05) in the lacrimal caruncle while those housed under the SO model with EE in the form of AB had a higher temperature in the nose compared to the other treatments. Infrared thermography (IRT) can be used as an effective tool to evaluate temperature differences in recently-weaned piglets due to the effects of environmental enrichment and social structure.