What's New in Old Horses? Postmortem Diagnoses in Mature and Aged Equids.
Authors: Miller M A, Moore G E, Bertin F R, Kritchevsky J E
Journal: Veterinary pathology
Summary
# Editorial Summary: Postmortem Disease Patterns in Older Equids Researchers at a teaching hospital examined necropsy findings from 241 equids aged 15 years or older to establish disease prevalence in geriatric populations and identify whether mortality patterns shifted between horses aged 15–19 years versus those 20 years and older. Digestive tract disease dominated the cause-of-death figures at 41.5%, followed by pituitary pars intermedia dysfunction (PPID) at 12.9% and locomotor problems at 10.0%, though age-related differences emerged: nervous system disease proved more prevalent in younger geriatric horses, whilst urinary tract conditions became increasingly significant in those over 20 years. Neoplastic disease accounted for nearly one-fifth of all deaths and euthanasias (18.7%), with squamous cell carcinoma, lymphoma, and melanoma predominating; among the 65 horses with confirmed PPID, nearly half (47.7%) were euthanased specifically due to pituitary disease, yet colic, lameness, cancer, and spinal cord disease represented the primary non-pituitary reasons for death in this subset. The findings reveal that whilst PPID is a significant and often terminal diagnosis in aged equids, a substantial proportion of older horses present with multiple concurrent pathologies—including neoplasia, infections, and orthopaedic deterioration—that may contribute to clinical decline independently or synergistically. For practitioners managing geriatric horses, this work underscores the importance of integrating PPID management with surveillance for concurrent colic risk, cancer, and neurological decline, particularly as horses progress beyond age 20.
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Practical Takeaways
- •Colic remains the primary life-limiting condition in aged horses; digestive system disease accounts for over 40% of deaths in horses ≥15 years old
- •PPID significantly impacts quality of life and longevity in aged horses; recognize that euthanasia decisions in PPID cases often involve multiple concurrent conditions (colic, lameness, cancer, neurological disease) rather than pituitary disease alone
- •Cancer prevalence increases with age; be alert to neoplastic presentations in geriatric horses, particularly squamous cell carcinoma, lymphoma, and melanoma
Key Findings
- •Digestive system disease was the leading cause of death/euthanasia in mature and aged equids (41.5%), followed by PPID (12.9%)
- •PPID was the most common specific diagnosis and reason for euthanasia in 47.7% of horses with confirmed PPID
- •Neoplastic disease accounted for 18.7% of all deaths/euthanasia, with squamous cell carcinoma, lymphoma, and melanoma being most prevalent
- •Nervous system disease was more common in horses aged 15–19 years, while urinary tract disease was more common in horses ≥20 years