Ovarian pain in the mare: clinical implications of mittelschmerz and oestrus‐related behavioural abnormalities

Mittelschmerz is a well-recognised benign peri-ovulatory pain syndrome in women and, by physiological analogy, may also occur in mares. In equine practice, peri-ovulatory ovarian pain has been associated with transient discomfort, colic-like signs and behavioural changes, although its true clinical relevance remains poorly defined. This narrative mini-review summarises current knowledge on the pathophysiology, clinical presentation, diagnostic challenges and management of ovarian pain in mares, integrating evidence from equine studies with established concepts derived from human medicine. In women, mittelschmerz is temporally associated with the luteinising hormone surge and prostaglandin-mediated ovarian smooth muscle contractions. Similar mechanisms have been proposed in mares, in which peri-ovulatory ovarian sensitivity may be detected during clinical examination but cannot be reliably used to predict ovulation. Behavioural abnormalities observed during oestrus are frequently attributed to ovarian activity or sex-steroid fluctuations; however, nonreproductive causes must be carefully excluded. In addition to physiological ovarian activity, both non-neoplastic and neoplastic ovarian disorders may induce chronic discomfort and behavioural alterations in mares, often posing diagnostic challenges due to overlapping ultrasono- graphic features with normal preovulatory follicles. Therapeutic strategies include hormonal suppression, induction of pseudopregnancy, immunisation against gonadotropin-releasing hormone and surgical intervention. While ovariectomy effectively resolves ovarian pain, its efficacy in correcting altered behaviour is variable. A multimodal diagnostic approach is essential to distinguish physiological ovarian pain from pathological conditions and behavioural disorders, thereby supporting appropriate clinical decision-making in equine practice.