[Heart rate fluctuations in the horse at rest: (2) Biological variation factors related to behavioural profile].

This research investigates the factors influencing heart rate variability in horses, such as age, sex, and breed, and correlates these factors with different behavioural patterns.

About the Study

• The research focused on analysing heart rate variability within a sample of 30 horses. This was to ascertain any influences of certain factors – age, sex, breed, and individual animal differences – related to varying behavioural patterns in these horses.
• The fluctuations in heart rate were studied by calculating the power spectral density of heartbeat interval series for each horse. The power spectral density is a measure that helps to understand the distribution of power into frequency components pertaining to the heart rate signal.
• A statistical method called the generalized linear model was employed to make comparisons between the spectra and to unveil the impact of each individual factor.

Findings of the Study

• The researchers discovered that the scale and shape of the spectral densities were markedly different between individual animals. This indicates that every horse has a unique heart rate pattern.
• These individual differences were partially justified by the influence of sex and age. In contrast, the breed factor appeared to have a minimal effect on heart rate variability. This suggests that the breed of the horse does not significantly impact its heart rate.
• Interestingly, it was observed that younger horses and mares (female horses) experienced a greater fluctuation in heart rate. This larger heart rate variability could be linked to higher ’emotionality’ or sensitivity to emotional responses, indicating a potential relationship between heart rate variability and emotional responses in horses.

Implications of the Research

• This research implies a potential to predict behavioural profiles, such as emotional sensitivity, in horses by analysing and understanding their heart rate variability patterns. It could be a new parameter for both health checks and behavioural studies in horses.
• From a largely health perspective, understanding heart rate variability patterns and their relationship to behaviour, age, sex, and other factors could also have diagnostic implications for horses, especially those demonstrating inconsistent or irregular heart rate fluctuations.