Mass Acorn Poisoning of Japanese Black Breeding Cattle

Abstract

In October 2019, 10 black Japanese breeding females at a beef cattle feeding facility presented with symptoms such as depression, poor appetite and diarrhea, and 9 of them died in approximately 3 weeks. Serum biochemical tests showed elevated levels of BUN and Cre. Acute tubular necrosis was found in all five cows for which the histopathological examination of the kidneys was carried out. The pericarp of the acorn of Quercus acutissima was detected in the feces gathered from the pasture and in the rumen contents of the dead cattle. The acorn contained a high concentration of total polyphenol, 6.08 dry matter % by the colorimetry method. Furthermore, polyphenols were also detected in all 4 dead cows whose ruminal contents were examined. Based on these results, we diagnosed this case as a mass acorn poisoning. A large number of acorns falling onto the pasture due to a large typhoon at a time when pasture grasses were scarce was assumed to be the cause of the event.