Individual differences in behavior and heart rate variability across the preweaning period in the domestic horse in response to an ecologically relevant stressor.

This study was conducted to understand individual differences in behavior and physiology among Azteca-breed foal’s response to stress by observing their response to maternal separation. The findings showed consistent individual differences from a very early age, which can potentially assist in future horse selection based on reactivity levels, impacting horse welfare and human safety and economy.

Objective of the Study

• The study aimed to investigate the presence of unique tendencies in behavior and physiological responses during the early development of domestic horses when they are exposed to stress. Specifically, the research sought to understand how foals react when briefly separated from their mothers, a situation that is relevant to their natural environment.
• The research also aimed to determine whether there exist correlations between individual behavior and heart rate variability.

Research Methodology

• The study involved a longitudinal setup involving 30 Azteca-breed foals that were observed from their first postnatal week till they were six months old, which is right before their weaning period.
• At various stages within the observation period, the foals were briefly separated from their mothers, and their behavioral responses and heart rate variability were monitored. This helped in understanding their stress levels and coping mechanisms.

Findings and Conclusions

• The findings indicated that individual differences in behavior and heart rate variability in response to brief maternal separation were consistently observable from a very early age in horses.
• These individual distinctions in behavior and physiological responses to stress were positively correlated. That is, specific behavioral patterns could predict certain physiological responses in the foals.
• The study’s insights can contribute to a more nuanced understanding of individual differences in behavior and physiological responses from a developmental perspective. This knowledge can be useful in future selection procedures involving horses, especially for functions that require different levels of reactivity.
• The overall findings of the research have implications not only for improving horse welfare, but also in the areas of human safety and economy.