FA GI Topics

Forestomach disorders and surgery

Bovine forestomach disorders include free gas bloat, frothy bloat, hardware disease, rumenitis/rumen acidosis, vagal indigestion, foreign bodies, grain overload/toxin ingestion, and omasal impaction. Surgery can be useful for bloat, hardware disease, foreign bodies, and grain overload/toxin ingestion. In cases of vagal indigestion, surgery can be useful to verify that there is nothing treatable (leading to euthanasia or culling).


Free gas bloat occurs when eructation is prevented. This can occur with high levels of gas production, esophageal obstruction or motility dysfunction. Extra gas accumulates due to more gas production with a change in diet, excessive fermentable feedstuffs or lack of eructation. A stomach tube can be placed into the rumen via the esophagus or red rumen trocar can be inserted into the rumen via a skin incision in the flank. The trocar will lead to rumen fluid leakage and some level of peritonitis.

Frothy bloat most commonly occurs due to ingestion of legumes (alfalfa, beans). Stomach tubing will not relieve a frothy bloat. The animal should be treated with a product designed to destabilize the froth (eg poloxalene).

Bloat is diagnosed by an “apple” appearance on the left side and a “pear” appearance on the right due to the distension of both the dorsal and ventral sacs of the rumen.

A ping will be present on the left, including with percussion on the transverse processes of the vertebrae. The distension can be palpated per rectum. Cattle may show signs of dyspnea due to pressure on the diaphragm. Death may occur if the bloat is not treated.

Differentials include esophageal obstruction or other cause of poor eructation.

Calves often develop recurrent bloat as they adjust to a more adult diet. It can take awhile for the rumen flora to adjust. A rumenostomy can be performed to allow gas to escape as needed until the problem resolves. These will close over eventually.

Grain overload/toxins

Rumenotomy can also be useful to remove the grain or toxins if the ingestion is identified early enough. As most of the ingest needs to be removed in these cases, transfaunation (providing rumen juice from a healthy cow) is recommended.

Omasal impactions

Omasal impactions rarely need direct treatment and are usually secondary to another issue. Treat the inciting cause and rehydrate the animal.

Rumenotomies and rumenostomies

‘Otomy’ refers to a temporary hole while an ‘ostomy’ is a permanent opening. In cattle, most all holes eventually close, so an ‘ostomy’ is open for awhile but not usually permanently. [“ectomy” refers to cutting something off]

Rumenotomy is indicated for vagal indigestion, , rumen acidosis and some forms of choke. Rumenotomy allows exploration of the rumen, reticulum and parts of the omasum.

Rumenostomy is performed in growing calves with chronic bloat and in any age ruminant to provide nutritional support. Rumenostomies can be performed instead of rumen trocarization for improved results. Rumenostomies are also performed for feed trials to enable direct feeding and/or sampling. Finally, a rumenostomy can be placed in an adult cow to provide easy access to microflora (rumen donor). Rumenostomies typically have smaller openings designed to close over time (calves) or are kept open with a rumen cannula sized to fit the cow and the need (feeding, fauna donor).


Microbial production of gas (physiology review)


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Large Animal Surgery - Supplemental Notes by Erin Malone, DVM, PhD is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License, except where otherwise noted.