Nuclear techniques for assessing and improving ruminant feeds : proceedings of a combined consultants meeting on nuclear techniques for assessing and improving ruminant feeds and of the first research co-ordination meeting on non-protein nitrogen and agro-industrial by-products utilization by ruminants with particular reference to developing countries organized by the Joint FAO/IAEA Division of Isotope and Radiation Applications of Atomic Energy for Food and Agricultural Development and held in Vienna from 30 November to 4 December 1981.