Case Report: Complex Plant Poisoning in Heavily Pregnant Heifers in Germany

Abstract

On a pasture five heavily pregnant heifers out of 15 animals in total developed severe apathy, haemorhagic enteritis as well as photodermatosis both at the mouth and vulva (mortality rate 80%). The vegetation of the 3-hectare pasture was recorded at species level. Both a botanical investigation of 500 g rumen content of one heifer and a quantitative analysis of cyanides in the blood of three animals were carried out. The sward consisted of fodder plants and reed sweet grass (Glyceria maxima), the latter a nutritious species containing cyanogenic glycosides. The blood samples contained up to 1.56 mg cyanide/l serum. Therefore, the heifers had eaten about 7 kg reed sweet grass, slightly less than the lethal amount. Marsh horsetail (Equisetum palustre) growing in between, was unintentionally ingested and caused haemorhagic enteritis. As a possible post-ingestive effect this could have evoked a positive selection of caraway (Carum carvi) as a remedy for stomach disorders in ruminants. 45% of the caraway population on the pasture had been grazed, one fragment having been found in the rumen. Photosensitising substances in caraway resulted in photodermatosis in the heifers. The complex finding underlined the need for an interdisciplinary approach in cases of suspected poisoning in general.