BEFORE you begin topping fields carry out a search for poisonous plants, ragwort especially. Any ragwort that is found should be pulled up and burned, this task is much easier after rain when the ground is soft. When ragwort is cut, pulled or poisoned by herbicides it becomes palatable to horses and the poison from ragwort acts on the liver creating a cumulative and long-term effect, which is usually fatal. Therefore it must be removed before topping commences.