Altrenogest treatment reduces the stress response of three-year-old warmblood mares during their initial equestrian training.

This research investigates the use of a hormone, altrenogest, in reducing stress responses in young female horses undergoing equestrian training. The study showed that altrenogest decreased stress reactions and positively influenced the horses’ body condition and weight during training.

Objective of the Study

• The main objective of the research was to study the effects of altrenogest, a type of progestin hormone, on the stress responses of young Warmblood female horses during their initial equestrian training. The researchers primarily sought to understand whether altrenogest can reduce stress-inducing behaviors associated with the estrous cycle in mares, which can negatively impact their performance during training.

Research Methodology

• Eleven Warmblood mares, aged three years, were divided into two groups. Six were given altrenogest (ALT), and five were given sunflower oil (CON).
• The mares were treated for twelve weeks during training. Salivary cortisol concentration and heart rate, recognized stress markers, were measured before and after training sessions.
• The stages of the training program included free movement, lunging without and with side reins, lunging with a saddle, and riding with different riders. The researchers also conducted periodic gynecologic examinations and two novel object tests.
• The horse’s body weight and body condition scores were routinely assessed.

Study Findings

• In both groups of horses, equestrian training sessions led to salivary cortisol and heart rate increases. However, the increase was less significant in the group treated with altrenogest, suggesting its stress-reducing effect.
• Gynecologic examinations and tests with novel objects caused a smaller cortisol and heart rate increase compared to equestrian training, with no difference between the ALT and CON groups.
• Initial training caused a decrease in bodyweight and body condition scores. However, these indicators increased more in the altrenogest-treated group in the subsequent period.

Conclusion

• Altrenogest was found to reduce the stress response in young mares during equestrian training. The improvement in bodyweight and condition scores in ALT-treated horses suggests an overall positive influence of altrenogest in their adaptive process to training.
• Despite the beneficial effects, the authors suggest that the use of altrenogest during competitions should be reconsidered due to its potential influence on performance, although further research would be beneficial to understand the implications fully.