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United States Department of Agriculture

Agricultural Research Service

Title: Post-Mortem Ruminal Changes in Sheep and Steers

Authors
item Cole, Noel
item Richardson, L - LILY RESEARCH LABS
item Stock, R - UNIVERSITY OF NEBRASKA

Submitted to: Agri Practice
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: July 7, 1997
Publication Date: N/A

Interpretive Summary: Beef cattle fed high concentrated diets in feedlots are susceptible to the metabolic disorder lactic acidosis, commonly called acidosis. Acidosis is caused by an excessive production of lactic acid by bacteria in the rumen and is usually the result of feed mixing errors, poor feed buck management or environmental stressors. Diagnosis of acidosis in animals that die is difficult, leading to the assertion by some consultants that acidosis is the most misdiagnosed disease of feedlot cattle. Rapid, simple, and accurate field diagnosis of acidosis is important in determining remedial actions that may be needed to reduce the incidence of the disease. This manuscript summarizes five experiments conducted in Nebraska, Indiana, and Texas to evaluate the postmortem changes which occur in the rumen of animals, in order to determine factors which can and cannot be used in the diagnosis of acidosis. These studies indicated that after death, the pH of fthe ruminal contents declined as a result of accumulation of volatile fatty acids. Lactic acid did not accumulate in the rumen postmortem. These results indicate that ruminal pH and lactic acid concentrations, common variables used to diagnose acidosis, are poor indicators of fatal acidosis in animals that have been dead for several hours. These results can be used by veterinarians to get a better diagnosis of the cause of death in feedlot cattle.

Technical Abstract: Five studies were conducted to determine the post-mortem changes in ruminal contents of sheep and cattle. Post-mortem ruminal pH values decreased and concentrations of volatile fatty acids increased significantly. The decrease in ruminal pH was apparently due to the increased ruminal VFA concentrations because lactate did not accumulate in any of the studies. Post-mortem ruminal changes appeared to be dependent upon the concentrate level of the diet as well as feed intake. These results indicate that ruminal fluid pH and/or lactic acid concentrations are potentially poor indicators of fatal acidosis in animals that have been dead for several hours.

Last Modified: 7/24/2014
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