Acute-onset high-morbidity primary photosensitisation in sheep associated with consumption of the Casbah and Mauro cultivars of the pasture legume Biserrula.

We report an unseasonal outbreak of acute photosensitisation in sheep grazing Biserrula pelecinus L cvs.'Casbah' and 'Mauro' with exceedingly high morbidity. A grading system is also proposed as a tool for objective and consistent clinical appraisal of future PS outbreaks. This finding expands our definition of seasonal and temporal risk periods for biserrula photosensitisation, and is the first to identify that both commercial cultivars of biserrula can cause primary photosensitisation in sheep.