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
# Editorial Summary: Altrenogest and Mare Behaviour Altrenogest is widely used in competition horses to suppress oestrus during competition seasons, sometimes continuously for several months, raising questions about whether this practice confers performance advantages beyond reproductive control. Hodgson and colleagues administered oral altrenogest at 0.044 mg/kg daily to 12 sedentary mares for eight weeks, monitoring changes in social hierarchy, activity levels, body mass and condition score. The eight-week treatment period produced no measurable effects on dominance interactions, physical development or body composition in the study population. For equine practitioners, these findings suggest that altrenogest use in mares does not appear to act as an anabolic agent or produce detectable behavioural changes under the conditions tested, though it's worth noting the study involved sedentary animals rather than competing horses under training stress. The results provide some reassurance regarding fairness in competition, though the specific demands of ridden work and higher activity levels in competitive environments may warrant further investigation.
Read the full abstract on PubMed
Practical Takeaways
- •Altrenogest used at therapeutic doses for oestrus suppression does not appear to confer unfair competitive advantage through anabolic effects or behavioral changes
- •Practitioners can use altrenogest for reproductive management without concern that it will alter dominance hierarchies or social stability within groups of mares
- •When used at recommended doses, altrenogest does not significantly impact body composition, simplifying management decisions for competition horses
Key Findings
- •Eight weeks of daily oral altrenogest (0.044 mg/kg) produced no effect on social dominance hierarchies in mares
- •Prolonged altrenogest administration resulted in no significant changes to body mass or body condition score
- •No evidence of anabolic or performance-enhancing properties at recommended therapeutic doses in sedentary mares