The call for products of animal origin increased dramatically in the Developing World in the last twenty years of the twentieth century. It is expected to double again in the first twenty years of the twenty-first century. The massive demand fuelled a concomitant increase in supply. This combination of events, being increasingly dubbed the “livestock revolution”, is certain to have an effect on the global environment. The changes that are occurring can be a force for good: helping to relieve human poverty, hunger and disease and being a driving force in intensification and improved efficiency of livestock production over wide areas.