Effect of paddock vs. stall housing on 24 hour gastric pH within the proximal and ventral equine stomach.
Authors: Husted L, Sanchez L C, Olsen S N, Baptiste K E, Merritt A M
Journal: Equine veterinary journal
Summary
# Editorial Summary Stall confinement has long been implicated in equine gastric ulcer syndrome development, yet the mechanistic link remained poorly understood. Husted and colleagues examined whether housing environment directly influences gastric acid exposure by monitoring 24-hour pH continuously in six horses fitted with gastric cannulae as they rotated through paddock grazing, stalled, and stalled-with-companion conditions on their normal forage and grain diet. Counter to prevailing assumptions, neither the proximal (just distal to the oesophageal sphincter) nor ventral stomach showed significant pH differences across the three housing situations; however, the proximal stomach exhibited a pronounced circadian rhythm with notably lower pH during the early morning hours (01.00–09.00), whilst ventral gastric pH remained remarkably stable regardless of time or environment. These findings suggest that housing alone does not directly alter acid exposure patterns and that ulcer risk factors associated with stalling may involve mechanisms beyond simple pH dysregulation—such as behavioural stress, reduced saliva production, feed particle size, or compromised mucosal perfusion—warranting investigation into these alternative pathways when addressing housing-related ulcer cases in practice.
Read the full abstract on PubMed
Practical Takeaways
- •Housing type (stall vs. paddock) may not be the primary driver of gastric ulcer development; other risk factors such as diet, stress response, or individual susceptibility warrant further investigation
- •The natural circadian rhythm of proximal gastric acid production occurs overnight/early morning (01:00-09:00 h), suggesting feeding schedules should account for acid exposure timing rather than assuming housing alone prevents ulcers
- •Current findings challenge the assumption that paddock turnout alone prevents ulcer formation—management of nutrition and feeding frequency may be more critical than housing environment
Key Findings
- •Housing status (paddock vs. stall alone vs. stall with companion) did not significantly affect 24-hour gastric pH in either proximal or ventral stomach regions
- •Proximal stomach pH demonstrated a circadian pattern with significantly lower pH between 01:00-09:00 h compared to 13:00-20:00 h
- •Ventral stomach pH remained uniformly stable throughout the 24-hour period regardless of time of day or housing environment
- •Stall housing alone was not identified as a direct risk factor for increased acid exposure in this controlled study