An Alternative Way to Evaluate Equine Stress: The Spontaneous Blink Rate

There are numerous scientific means with which we can evaluate our horse's stress. These can include measuring heart rate variability as well as cortisol levels. These are invasive and require specialized equipment to calculate. Of course, we frequently monitor vital signs including temperature, respiratory rate and heart rate. But what if we considered adding another measure to help us gain insight into what our horse is feeling? The spontaneous blink rate of horses can serve as an important indicator of their emotional and physiological state, particularly under stress. Understanding this relationship can provide insights into equine welfare and behavior.

Understanding Spontaneous Blink Rate

Spontaneous blink rate refers to the frequency at which an individual blinks without any external stimuli. In horses, this rate can vary based on several factors, including:

• Environmental conditions

• Social interactions

• Health status

• Stress levels

  
  

Impact of Stress on Blink Rate

When horses are exposed to stressors, their blink rate may change as a response to their emotional state. Some key points to consider include:

• Increased Blink Rate: Under acute stress, horses may exhibit an increased blink rate as part of their fight-or-flight response.

• Decreased Blink Rate: In some cases, chronic stress may lead to a decreased blink rate, indicating a state of heightened alertness or anxiety.

• Behavioral Indicators: Changes in blink rate can be accompanied by other behavioral signs of stress, such as pacing, head tossing, or changes in posture.

If you're like me and you'd love to nerd out on the science, I've referenced a study performed by Mott et al (2020) below, where they demonstrated that spontaneous blink rate is a viable instantaneous measure of acute equine stress. Understanding these physiological responses can help in developing better management practices to enhance equine welfare. When working with your horse, I will be paying attention to blink rate as one of the indicators of stress or relaxation.

Reference:

Mott, R. O., Hawthorne, S. J., & McBride, S. D. (2020). Blink rate as a measure of stress and attention in the domestic horse (Equus caballus). Scientific Reports, 10(1). https://doi.org/10.1038/s41598-020-78386-z