Gross Pathology of Ruminal Tympany and Acute Congestive Heart Failure in an Adult Crossbred Dairy Cow

Abstract

This paper reports a case of ruminal tympany and acute congestive heart failure (ACHF) encountered at necropsy of a crossbred dairy cow. On 21 July 2025, the cow was found dead in the morning in a dairy cattle farm composed of crosses of Friesian, in Mbeya City, Tanzania. According to the animal attendant, the previous daytime the animal had normal appetite and did not show any clinical signs. The owner requested a necropsy service to establish the cause(s) of death of the cow. Necropsy revealed abdomen and rumen distension, excessive accumulation of fermentation gases in the rumen, pulmonary congestion, flabby myocardium, cardiac chambers dilatation, and about one kilogram of a thrombus in the cardiac chambers as gross pathological findings. Based on history and the findings, the animal was diagnosed to have died of primary ruminal tympany and ACHF due to entrapment of normal gases of fermentation in stable foams after ingestion of bloat-causing forages which produce stable foams, and dilated cardiomyopathy, respectively. The diagnosis of primary ruminal tympany was reached after ruling out secondary ruminal tympany due to lack of characteristic gross pathological findings. Dilated cardiomyopathy was diagnosed as the cause of ACHF after excluding other cardiac diseases based on absence of pathognomonic lesions. Although both ruminal tympany and ACHF are common, their co-occurrence as cause of death is rare. In this case the stress of ruminal tympany could have exacerbated a pre-existing subclinical dilated cardiomyopathy leading to ACHF.  Dilated cardiomyopathy is a hereditary disease. In cattle the diseases has been reported in different breeds and countries including Simmental-Red Holstein in Switzerland; Holstein-Friesian in Canada, Australia, the United Kingdom, the Netherlands, Switzerland, Japan, Sweden, and Denmark; and Red Danish Dairy, Holsteins, and Red Holsteins in Denmark. Having a genetic etiology, the occurrence of dilated cardiomyopathy in the cow could be associated with the importation of bulls, heifers, and semen for breeding purposes from countries affected by dilated cardiomyopathy; and being a cross of Friesian, the genotype of the cow could have predisposed her to dilated cardiomyopathy.