Climate change impact on blood haemogram in the horse: a three-year preliminary study.
Authors: Deniz Ömer, Aragona Francesca, Murphy Barbara A, Tümer Kenan Çağrı, Bozacı Serkan, Fazio Francesco
Journal: Frontiers in veterinary science
Summary
# Editorial Summary Over a three-year period (2021–2023), researchers monitored 25 Thoroughbred mares in Turkey to determine whether seasonal climate variations affect equine blood parameters, collecting monthly blood samples alongside environmental data including temperature, humidity, and the Temperature-Humidity Index (THI). The study revealed significant seasonal patterns in multiple haematological markers: red blood cell count and mean corpuscular haemoglobin declined progressively each year, whilst haemoglobin concentrations dropped consistently during summer months and again in autumn 2023; notably, white blood cells increased throughout spring periods, with elevated lymphocytes and monocytes recorded in April. These findings suggest that climate-driven physiological stress produces measurable changes in equine haematology that extend beyond simple seasonal variation, indicating a progressive year-on-year impact. For practitioners, this research underscores the importance of establishing individual baseline haematological profiles and accounting for seasonal–climatic context when interpreting blood work, as environmental stress may predispose horses to disease or mask underlying conditions; monitoring these parameters could support both welfare assessment and early identification of climate-related health challenges in working and breeding populations.
Read the full abstract on PubMed
Practical Takeaways
- •Monitor blood parameters seasonally, particularly red cell metrics in summer and WBC counts in spring, as climate-driven changes may otherwise be misinterpreted as disease
- •Be alert for potential welfare concerns during peak summer heat, when multiple haematological markers (RBC, HGB, HCT) decline, possibly indicating heat stress or dehydration
- •Establish individual baseline haemograms for horses in different seasons and climatic zones to distinguish normal seasonal variation from pathological changes requiring intervention
Key Findings
- •Red blood cell count, mean corpuscular hemoglobin, and hemoglobin decreased significantly in summer months across all three years (p<0.01 to p<0.0001)
- •White blood cell levels increased during spring periods in 2021 and 2022, with elevated lymphocytes and monocytes in April 2021 (p<0.0001)
- •Mean corpuscular hemoglobin concentration increased in July-August 2021-2022 and June 2023, suggesting seasonal variation in red cell indices
- •Hematocrit and mean corpuscular volume showed decreasing values in autumn 2022 and 2023, indicating sustained seasonal effects across multiple years