Blood splash in lambs-a preliminary study using the one-stage prothrombin time test

Lambs from a flock in which a high incidence of blood splash had been detected were examined using the one-stage prothrombin test. For comparison lambs from a commercial slaughter line were also examined. All the affected lambs and 35·4% from the slaughter line had extended prothrombin times, and a relationship between extended prothrombin times and the occurrence of blood splash was established. Investigation of the pastures grazed by the affected flock showed the presence of coumarin producing plants and grasses. Some coumarin drugs prolong one-stage prothrombin times, and more importantly, induce capillary fragility, thus predisposing animals to blood splash.