Investigation of the effect of pasture and stable management on large intestinal motility in the horse, measured using transcutaneous ultrasonography
Authors: WILLIAMS S., TUCKER C. A., GREEN M. J., FREEMAN S. L.
Journal: Equine Veterinary Journal
Summary
# Editorial Summary Management regime significantly influences large intestinal motility in horses, with stabled animals demonstrating markedly reduced contractility compared to pasture-kept counterparts—a finding that may explain the elevated colic risk associated with confinement. Using transcutaneous ultrasonography to measure contractions across the caecum, sternal flexure and aboral left ventral colon, Williams and colleagues conducted a crossover study in 16 working horses, recording motility twice daily over consecutive days under both management conditions; the results showed consistent reductions in stabled horses across all measured regions, most notably in the left ventral colon (0.7 versus 1.0 contractions/min). Beyond documenting these physiological differences, the research provides objective evidence supporting the mechanistic link between stable management and large intestinal impaction colic, suggesting that practitioners should consider grazing opportunities and movement patterns as integral components of colic prevention strategies rather than purely nutritional or hydration interventions. For farriers, veterinarians and rehabilitation specialists involved in managing at-risk horses, these findings reinforce the importance of advocating for pasture turnout or, where this is impractical, designing stable management protocols that maximise movement and foraging behaviour to optimise gastrointestinal function.
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Practical Takeaways
- •Stabled management reduces large intestinal motility by 20-30%, particularly in the left ventral colon—this provides a mechanistic explanation for why stabled horses are at higher risk of colic and impaction
- •Maximize pasture turnout time where possible, or if stabling is necessary, ensure increased activity/exercise and hay-based feeding to maintain intestinal function
- •When assessing intestinal motility via ultrasound, standardize measurement timing and location, as both time of day and anatomical site significantly affect readings
Key Findings
- •Large intestinal motility was significantly lower in stabled horses compared to pasture-kept horses across all measured sites (caecum, sternal flexure, left ventral colon)
- •Caecal motility decreased from 2.0 to 1.4 contractions/min, sternal flexure from 1.7 to 1.5 contractions/min, and left ventral colon from 1.0 to 0.7 contractions/min when moving from pasture to stabled management
- •The reduction in motility was most pronounced in the aboral left ventral colon, suggesting a management-dependent mechanism for impaction risk
- •Time of day and intestinal region significantly influenced motility measurements, indicating the importance of standardized assessment protocols