Abnormal mare behaviour is rarely associated with changes in hormonal markers of granulosa cell tumours: A retrospective study.
Authors: Huggins Lauren, Norris Jamie, Conley Alan, Dini Pouya
Journal: Equine veterinary journal
Summary
# Editorial Summary Abnormal behaviour in mares is frequently attributed to ovarian pathology, yet this retrospective analysis of 2,914 hormonal profiles submitted for behavioural concerns reveals a more nuanced picture. Researchers examined associations between reported behavioural abnormalities and hormonal markers typically elevated in granulosa cell tumours (testosterone, anti-Müllerian hormone, inhibins and inhibin-B), using Chi-squared statistical analysis to determine whether increased hormone concentrations correlated with specific behavioural presentations. The striking finding was that 86% of cases presented for behaviour issues showed no GCT-associated hormonal elevation whatsoever, whilst amongst the remaining 408 cases with elevated markers, only stallion-like behaviour demonstrated a statistically significant association—behaviours including aggression, oestrous abnormalities and other undesirable presentations were significantly *less* likely to correlate with raised hormone concentrations. For practitioners, these results challenge the common clinical assumption that ovarian dysfunction underpins most behavioural problems in mares, suggesting that investigation and management should consider non-ovarian aetiologies (such as pain, environmental factors, learning history and neurological causes) before attributing behavioural change to reproductive endocrinopathy; testosterone elevation alone was documented in only 7.7% of behaviour-related submissions, making routine endocrine screening an inefficient diagnostic approach for general behavioural concerns.
Read the full abstract on PubMed
Practical Takeaways
- •Abnormal mare behaviour (aggression, oestrous issues) is rarely caused by ovarian pathology—investigate other causes before assuming hormonal origin
- •Stallion-like behaviour is the only behavioural presentation reliably associated with elevated ovarian hormones and warrants hormone testing
- •Hormonal testing for GCT should be targeted based on specific behaviour patterns rather than used as a blanket investigation for all behavioural complaints
Key Findings
- •86% of 2914 mares submitted for behaviour issues had no hormonal markers consistent with GCT
- •Only stallion-like behaviour was significantly associated with increased testosterone, AMH, inhibins and inhibin-B concentrations
- •Aggression, oestrous and other abnormal behaviours were significantly less likely to be associated with elevated ovarian hormones
- •Among hormone-elevated cases, 63% had one hormone elevated, 25.5% had two, and 11.5% had three hormones at GCT-like concentrations