Behavioral and physiological responses of young horses to different weaning protocols: a pilot study.

This study explores the impact of various weaning techniques on the stress levels of young horses, finding that weaning leads to stressed behavior, but that this can be minimized by weaning in the presence of two familiar, yet unrelated adult females.

Study Overview

• The research investigates the physiological and behavioural responses of foals weaned under different protocols. By observing these responses, the study aims to assess the amount of stress put on the foals during the weaning process.
• Three groups of foals were weaned in separate ways: those weaned simultaneously without adult horses present (group A), those weaned in the company of two familiar but unrelated adult females (group B), and those where two mother horses were removed per day (group C).
• Various aspects of the foals were studied, including behavior, movement, salivary cortisol concentration (a standard stress marker), beat-to-beat (RR) interval, heart rate variability (HRV) and weight changes.

Key Findings

• Group A foals lost weight, with the loss being most notable within the first two days. This group also displayed the most significant decrease in RR intervals. These factors could suggest higher stress levels in this group.
• All groups showed increased vocalization post-weaning, but the rise was least noticeable in group B (the foals weaning in the presence of two unrelated female horses). Group B also showed the lowest increase in locomotion on weaning day.
• The major stress indicator measured in this study – salivary cortisol concentration – increased on the weaning day for groups A and B, and continued to rise for two days in group C.
• However, no consistent changes were observed in Heart Rate Variability (HRV) across the groups.
• The study concludes that whilst weaning is associated with stress, it is minimized when foals are weaned in the company of two familiar but unrelated adult horses, indicating that this weaning method could be the least stressful for the foals.