Abstract
Throughout the world, several hepatogenous photosensitisation diseases of ruminants are characterised by the presence of birefringent crystals in and about the bile ducts. These include photosensitisations caused by Tribulus terrestris Citation(1) (geeldikkop of sheep in South Africa), Nurthecium ossifrugum Citation(2).(alveld of lambs in Norway), Agave lecheguilla Citation(3) Citation(4), Brachiaria decumbens Citation(5) and several Panicum species such as P miliaceum Citation(6), P. coloratum Citation(7), P. schinzii Citation(8) Citation(9), and P. dichotomiflorum Citation(10).