Can changes in nasal temperature be used as an indicator of emotional state in cows?

We found that both positive and negative high arousal experiences cause a significant reduction in the nasal temperature of cattle. The introduction of a positive contrast; highly favoured 'concentrates' feed, following a conditioned neutral feed stimulus, elicited the emotional state of excitement and resulted in a significant decrease in nasal temperature (F (1.90,376.16) = 17.36, p < 0.001). As did the negative contrast; an inedible feed following a conditioned positive feed stimulus, which is considered to elicit the emotional state of frustration (F (2,84) = 8.41, p < 0.001). These findings, suggest that significant drops in nasal temperatures are a result of a change in emotional valence, and not descriptive of the type of valence, or a change in arousal. Further research needs to be conducted as there is so little known about the effects of emotional state on peripheral temperatures, particularly positive emotional states. Our findings support previous research to suggest that there is potential for nasal temperatures in cattle to be used as a reliable indicator of changes in emotional valence, although much more needs to be done before we can draw concrete conclusions regarding the effects.