Studies on the potential pyrrolizidine alkaloid load of Galloway cattle in year-round grazing on areas with tansy ragwort (Senecio jacobaea L.)

The native tansy ragwort (Seneciojacobaea L.) is regularly under suspicion to be the causative agent of poisoning in Iivestock.The pyrrolizidine alkaloids produced by the plant are metabolised in the liver to form toxic pyrroles, which may lead to both acute and chronic symptoms of intoxication depending on the amount and period of intake. Besides the aspects of animal health, a potential passage of PAs into the food chain must be evaluated. In this study, data on the potential exposure of year- round grazing Galloway cattle on pastures in Schleswig-Holstein with and without ragwort growth were compared. Tissue samples of liver, muscle and fat were collected for PA-analysis by LC-MS/MS. In addition, livers underwent histological examination and blood samples were collected at the time of slaughter. In all tissue samples tested, PA-content was below the limits of detection.The results of the histological examination of livers did not indicate any of the typical PA-associated signs (cirrhosis, necrosis, tumorai lesions, mitotic dysfunctions).Though a high number of animals displayed signs of portal fibrosis, reactive/ reparative changes and lymphocytic hepatitis, these changes were equally distributed in both groups (ragwort/control). For the analysed blood parameters, no statistical differences could be shown between control group and ragwort group.The results show that, for robust cattle in an intact herd structure, grazing on areas with dense ragwort growth does not lead to additional health impairments compared to grazing on areas without ragwort growth and that the animals are able to cover their energy requirements sufficientiy on these pastures.