FieldDxChronic Free-Gas BloatClinical signs, differential diagnosis, treatment and prevention.
Overview
Persistent gas accumulation in the rumen when eructation is physically or neurologically blocked, rather than from trapped foam. Gas fails to escape because of oesophageal obstruction, pressure from outside the oesophagus or disrupted eructation nerve reflexes; chronic cases are linked to vagal indigestion and diaphragmatic hernia.
Clinical signs
- Excess gas sits above the ingesta, giving tympanic resonance over the left dorsal abdomen.
- Percussion gives a higher-pitched ping than frothy bloat.
- Passing a stomach tube or trocar releases gas and relieves distension at once.
Predisposing factors
- Chronic calf ruminal tympany without apparent cause usually resolves on its own.
- Cattle cast in dorsal recumbency or restrictive positions can die of bloat.
Look-alikes to rule out
Treatment
- Acute episodes are relieved by passing an orogastric tube into the rumen, with antifoaming agents or emergency rumenotomy if needed; an esophageal obstruction is removed if that is the cause.
- For animals with recurring chronic bloat, a surgically created rumen fistula can vent gas for 60-90 days until it heals over.
Source
MSD Veterinary Manual — Bloat in Ruminants (accessed 2026-08-12)
MSD Veterinary Manual — Bloat in Ruminants (accessed 2026-10-29)
Condensed and attributed, never reproduced whole. Open the full entry in the app.