Spontaneous and experimental poisoning by Quercus robur (English oak) in bovine in Uruguay

Abstract

Three outbreaks of intoxication by Quercus robur L. (Fagaceae) are described for the first time in Uruguay. Spontaneous cases occurred in May (autumn) of 1997, 2001 and 2013, all in the department of Maldonado where it is common the existence of large oak forests. Fifteen of 90 1- years-old steers were affected in 1997, 7 of 74 in 2001 and 10 of 60 in 2013, with a case fatality rate of 26.6% , 14.2% and 30.0%, respectively. The animals showed constipation, weakness and progressive loss of weight, uremia with elevated levels of urea and creatinine. Pale kidneys, perirenal edema and ulceration of the esophagus were found at necropsy and severe toxic nephrosis at histopathology. Acorns were found in the rumen contents of one of the necropsied animals. The disease was confirmed experimentally in two calves 5-6 months of age, which were dosed orally with 22.8 kg 10.7 kg of acorns and leaves of Quercus robur, divided in several doses of 15-30 g/kg during 22 and 30 days, respectively. In both experimental animals, macro and microscopic examination showed perirenal edema, pale kidneys and acute tubular nephrosis, lesions comparable to field cases which confirm the spontaneous poisoning by Quercus robur.