Effect of prolonged use of altrenogest on behaviour in mares.
Authors: Hodgson David, Howe Stephanie, Jeffcott Leo, Reid Stuart, Mellor Dominic, Higgins Andrew
Journal: Veterinary journal (London, England : 1997)
Summary
# Altrenogest and Mare Behaviour: Implications for Competition Use Altrenogest is widely used in competition horses for oestrus suppression during competitive seasons, with some animals receiving continuous treatment for several months, yet questions remain about whether this progestin might confer performance advantages beyond cycle control. Hodgson and colleagues administered 0.044 mg/kg altrenogest daily to 12 sedentary mares for eight weeks, systematically measuring changes in social hierarchy, activity patterns, body mass and condition scoring to determine whether the drug possessed anabolic or other ergogenic properties. The eight-week treatment period produced no significant effects on dominance relationships, activity budgets, body mass or body condition score compared with control periods. These findings provide reassurance that prolonged altrenogest use at recommended therapeutic doses does not appear to offer unfair performance advantages through alterations in physiology or behaviour, though practitioners should note this study was conducted in sedentary animals and may not fully represent the demands of competition horses under high performance conditions. The results support the continued use of altrenogest as a legitimate management tool for oestrous cycle suppression without concerns about undisclosed performance enhancement in mares.
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Practical Takeaways
- •Altrenogest used at recommended doses for oestrus suppression does not provide unfair performance advantages through changes in body composition or dominance behaviour
- •Practitioners can be confident that therapeutic altrenogest administration will not alter the social dynamics or physical condition of treated mares in a way that would unfairly advantage competition horses
- •This evidence supports the safety profile of altrenogest for routine equestrian use without concern for unintended performance-enhancing effects
Key Findings
- •Prolonged oral altrenogest (0.044 mg/kg daily for 8 weeks) had no effect on social dominance hierarchies in sedentary mares
- •No significant changes in body mass or body condition score were observed following 8 weeks of altrenogest administration
- •Altrenogest did not alter activity budgets in treated mares
- •No anabolic or performance-enhancing effects were detected at recommended therapeutic doses