Stress response of 18-, 24- and 30-month-old sport horse stallions to a pretraining programme.

The research study investigates the stress responses of young sport horse stallions to a pretraining program designed for stallion licencing, using parameters such as salivary cortisol concentration, heart rate and heart rate variability (HRV). The researchers found that all stallions experienced a stress response to pretraining events, indicating both physical and mental demand. However, repetition reduced the stress response significantly, and even the youngest stallions rapidly adapted to these demands, regardless of their housing situation.

Research Undertaken

• The researchers investigated the stress response of young stallions to a pretraining programme that included free movement in an indoor arena, training in a horse walker, lunging and jumping obstacles without riders. Among the stallions studied were 24 and 30 month olds housed in groups or individual boxes, and group-housed 18-month-old stallions who only participated in a reduced programme.
• The study measured stress response based on the concentration of salivary cortisol, heart rate, and heart rate variability (HRV) before and after the pretraining period, in both the group and individual housing conditions.

Findings

• It was found that all the stallions regardless of age or housing type, exhibited an increased cortisol concentration and heart rate in response to pretraining events, indicative of a stress response. This response, however, decreased with the repetition of events.
• While initially, the stress response was more pronounced after free movement exercises, it waned with repeated exposure.
• Interestingly, when horses were placed in the horse walker for the first time, group-housed stallions displayed a higher cortisol release compared to individually housed ones.

Conclusions

• The study concludes that pretraining for young stallions involves both physical and mental demands and triggers a stress response. However, these reactions diminish significantly with the repetition of events, indicating adaptability even in stallions as young as 18 months.
• Moreover, the researchers found that group housing did not have any significant stress-reducing effect in the context of the pretraining program.
• The study provides no firm evidence suggesting that systematic pretraining for young Warmblood stallions raises animal welfare concerns.