Nigel W. Tomkins, Livestock Industries, Commonwealth Scientifc and Industrial Research Organisation, Ibis Avenue, North Rockhampton Queensland 4702, Rockhampton, Australia, Suzanne Kearins, Brunette Downs Station, Australian Agricultural Company, PMB 5 Mt Isa, Queensland 4825, Mt Isa, Australia, and Harmony James, Pastoral Production, Department of Primary Industries Fisheries and Mines, Barkly House, Paterson Street Northern Territory, Tennant Creek, Australia.