Blood lactate concentrations in ponies and miniature horses with gastrointestinal disease.
Authors: Dunkel B, Kapff J E, Naylor R J, Boston R
Journal: Equine veterinary journal
Summary
# Editorial Summary Elevated blood lactate in horses with colic is traditionally interpreted as a marker of severe, possibly surgical disease, but this retrospective analysis of 50 ponies and 100 matched horses presenting with gastrointestinal disease reveals that breed physiology substantially complicates this interpretation. Ponies demonstrated significantly higher median lactate concentrations on admission (2.8 mmol/l versus 1.6 mmol/l in horses; P = 0.001) despite comparable colic severity, alongside higher respiratory rates, rectal temperatures, and longer duration of clinical signs before presentation. Notably, within several disease categories—including large intestinal lesions, non-strangulating conditions, and medically-managed cases—ponies maintained elevated lactate values regardless of treatment type or outcome, whereas horses showed the expected inverse relationship between lactate concentration and survival. These findings carry important diagnostic implications: applying equine-derived lactate thresholds to ponies risks misinterpreting metabolic acidosis as a poor prognostic indicator or surgical emergency when the elevation reflects normal breed physiology rather than disease severity. Practitioners should factor breed-specific lactate baselines into clinical decision-making to avoid unnecessary exploratory laparotomy and ensure treatment decisions in small equines are grounded in breed-appropriate reference values.
Read the full abstract on PubMed
Practical Takeaways
- •Do not interpret elevated blood lactate concentrations in ponies and miniature horses with colic the same way as in large breed horses—breed-specific reference ranges may be needed to avoid false suspicion of surgical lesions or poor prognosis
- •Ponies with GI disease consistently show higher vital signs (respiratory rate, temperature) and higher lactate levels as normal variants; use these as context when assessing colic severity and treatment decisions
- •Blood lactate concentration alone is less predictive of outcome in ponies compared to horses, so rely on additional clinical and diagnostic parameters when determining whether surgery is indicated
Key Findings
- •Ponies with gastrointestinal disease presented with significantly higher median blood lactate concentrations (2.8 mmol/l) compared to large breed horses (1.6 mmol/l; P = 0.001)
- •Ponies had higher respiratory rates (27 vs 21 beats/min) and rectal temperatures (37.9 vs 37.4°C) than horses with similar disease
- •Blood lactate concentrations in ponies did not differentiate between surgical and medical lesions, or between surviving and non-surviving cases, unlike in horses
- •Ponies presented with longer median duration of clinical signs (10 hours vs 6 hours) before seeking treatment