Measuring emotions in cows: What can nasal temperature tell us?
Proctor, H., & Carder, G. (2016). Can changes in nasal temperature be used as an indicator of emotional state in cows?. Applied Animal Behaviour Science, in press
Finding measures of animal emotions is a new, but important, area of scientific research. This study explores the possibility of using nasal temperature as an indicator of emotional state in dairy cows.
Good animal welfare not only requires consideration of an animal’s physical state, but also their emotional well-being. Therefore, understanding how to measure animal emotions is an important area in animal welfare science. To date, there is very little research that has explored the use of peripheral areas such as nasal temperatures as a measure of emotional state in animals. You may wonder why different emotions may cause a change in peripheral temperatures. To summarise, in mammals physical and emotional stress is known to cause a short-lived increase in core body temperature, known as emotional fever. During such states, the blood is diverted away from non-vital areas of the body such as the nose, and towards essential areas, such as the brain. Therefore, temperature changes in peripheral areas could offer a non-invasive way to measure changes in core body temperature.
Previous research has found that the eye temperatures of cows drop in response to negative situations, in a previous study the authors found that nasal temperature of cows decreased in response to positive, low arousal emotional states. It was suggested that this may have resulted from a change in emotional valence.
Positive, neutral and negative emotions
In this study, the cows were presented with three treatments: a positive stimulus (concentrates feed), a neutral stimulus (standard feed), and a negative stimulus (inedible woodchip). Using a non-invasive infrared thermometer gun, the nasal temperature of the cows was measured during exposure to the three treatments. Results showed that the cows’ nasal temperature significantly dropped when presented with the inedible woodchip. Nasal temperature also dropped when the cows were presented with the concentrates feed. However, when exposed to the standard feed the nasal temperature remained constant. The authors concluded that the drop in nasal temperature could result from a change in emotional state. When the cows received the positive treatment they were expecting the neutral treatment. Also when the cows received the negative treatment, they may have been anticipating the positive concentrates feed. Both resulted in a change in emotional state, possibly excitement and frustration.
More work is needed to explore the use of peripheral areas as measures of emotions in cows, and other animals too. Once tested, this measure could be a very useful tool for animal welfare scientists.
World Animal Protection’s view
World Animal Protection believes that finding objective, non-invasive ways to measure animal emotions is important. If we can understand how animals express both positive and negative emotions, we can work towards providing better welfare.