Dale A. Yarns

Document Type

Thesis - Open Access

Award Date


Degree Name

Master of Science (MS)

Department / School

Dairy Science


Bloat may spell disaster to any farmer on a given day. This kind of disaster is typical and not infrequent in ruminates especially cattle and sheep. Bloat affects polygastrics, why not monogastrics? Ruminants or polygastrics have a four compartment stomach utilizing protozoa and bacteria similar to a fermentation vat which catabolizes complex substrates into simple digestible nutrients while the monogastrics rely on secretions from the stomach lining. Primarily fermentation takes are water and larger amount of free gas, which can accumulate in the rumen when disposal is impaired. Why do animals dispose of these large quantities of gas 364 days out of a year and the following day die because of the inability to discharge this gas? Some investigators suggest that the rumen is unable to function when certain soft materials such as alfalfa are the primary components of the diet. The addition of scabrous materials to the ration is believed to be beneficial for stimulation eructation and the elimination of gas. Others believe that drugs such as penicillin and aureomycin will inhibit gas production sufficiently to prevent bloat. Still another theory is based on evidence that a toxic material is present at times in sufficient quantity to cause death. Despite voluminous amounts of research done in the field of bloat the cause of bloat and the cause of death are still vague. The toxic theory has not been disproven completely, therefore, this seems to be as vital to the overall bloat picture as any. After choosing the toxic theory the assumption that the toxicity would be found in the blood was made. Carbon dioxide, pseudocholinesterase, and methemoglobin were choose are the compounds in the blood which might the greatest potential for causing bloat symptoms or death.

Library of Congress Subject Headings

Bloat in animals


Includes bibliographical references (pages 45-49)



Number of Pages



South Dakota State University


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Dairy Science Commons