FA GI Diagnostics & GI Surgery Principles
Cows do not show pain unless mesenteric traction is involved. Cows with LDAs, RDAs and even abomasal volvulus are off feed and may be recumbent but do not kick at their belly or show classic colic signs. Cows with peritonitis may show abdominal pain on local pressure or may show abdominal splinting (reluctance to scootch) but not obvious colic.
If a cow is kicking at her belly (even once or twice) or is restless, it is a sign of a surgical lesion and she should be explored (right flank). Referral isn’t a bad idea as she is likely to go down during surgery.
Cows with anemia generally have abomasal ulcers. These cows are generally early lactation and often first calf heifers. Older animals that are anemic and in midgestation should be evaluated for bovine lymphosarcoma.
Abdominal fluid is obtained to the right of midline (the rumen is on midline) and just above the udder. Ultrasound can help identify fluid pockets.
However, cattle are do good at walling off infection that they can have localized peritonitis and have a normal abdominal tap.
Lack or decreased manure generally indicates a partial (DA) or full obstruction. Obstruction can be physical but is often functional (nerve or muscle damage)
Fresh blood indicates a distal lesion and is seen with coccidia, trauma, intussuception and hemorrhagic bowel syndrome. Melena is digested blood and often indicates abomasal ulcers
With abomasal outflow obstruction, abomasal content backs up into the rumen, lowering the chloride and killing the normal flora. Animals that have been off feed will also change flora as the cow’s diet is primarily feeding the flora. No good diet, no good flora. High concentrate diets also change the flora.
Adult cows with GI lesions usually have metabolic alkalosis. Low chloride levels indicated abomasal outflow obstruction and can be used to localize lesions.
Cattle with GI issues can have associated atrial fibrillation. This usually resolves when the GI issue is fixed.