A Czech zoo has begun sawing off the horns of its 21 rhinos in order to protect them from poachers.<br />It follows the killing of a rhinoceros in France earlier this month.<br /><br /> The zoo near Prague keeps 17 black rhinos and four southern white one.<br /><br /> The animals are first anaesthetised but the procedure itself is not painful.<br /><br /> Global trade in rhino horn is banned by the United Nations but demand is high in some Asian countries where it is used in traditional medicines.<br />
