[Experimental trial to reproduction enzootic haematuria in cattle by feeding bracken fern [Pteris aquilina (Kuhn)] (author's transl)].

: Cattle were fed with a diet containing bracken fern in order to study the development of chronic bovine haematuria. The experimental 25 animals were randomly divided into 5 groups and such groups received different amounts of the plant. All groups were fed for 36 months, while no clinical effect of the disease was noted. After that time, the supplement of bracken fern to the diet was suspended and the animals still remained under observation. One of the animals (from group I) exhibit haematuria one month after the fern was removed from the diet. In the same occasion, four animals were slaughtered and only one of them presented haemorragic lesions in the urinary bladder. After 34 days another four animals were slaughtered and 114 days later three more were killed. All animals were chosen randomly and in spite of no clinical signs of the disease, all of them presented haemorragic lesions in the urinary bladder. The results obtained in this experiment confirmed that bracken fern (Pteris aquilina) is responsable for the development of chronic bovine haematuria in cattle. The disease is challenged by continuous ingestion of small amounts of bracken fern during a long period of time.