Animal production in Australia : proceedings of the Australian Society of Animal Production, volume 20, twentieth biennial conference [preliminary information]

Abstract

Animal Production in Australia PROCEEDINGS OF THE AUSTRALIAN SOCIETY OF ANIMAL PRODUCTION VOLUME 20 TWENTIETH BIENNIAL CONFERENCE THE UNIVERSITY OF WESTERN AUSTRALIA, PERTH, WESTERN AUSTRALIA, JULY 1994 Copyright 0 1994 Australian Society of Animal Production Printed in Australia by: Perth Print Brokers Typesetting by: Haymarket Pty Ltd ISSN 0728-5965 All rights reserved. No part of this publication may be reproduced, stored in a retrieval system or transmitted in any form or by any means, electronic, electrostatic, magnetic tape, mechanical, photocopying, recording or otherwise, without permission in writing from the Australian Society of Animal Production. OFFICE BEARERS, 1992 - 94 President President-Elect Vice-President Honorary Secretary Honorary Treasurer Co-editors of the Proceeding of the 20th Biennial Conference Mr I.P. Barrett-Lennard Dr J.H. Ternouth Dr J.B. Mackintosh Dr K.P. Croker Dr W.J. Ryan Drs D.G. Masters and J.G. Allen COUNCIL MEMBERS Dr S.K. Baker (Convenor, Program Sub-Committee from February 1994) Dr K.J. Bell Dr J.A. Fortune (Convenor, Program Sub-Committee, resigned January 1994) Mr M. Humphry MS S. Knight (to March 1994) Prof. D.R. Lindsay (Convenor, Publicity Sub-committee) Mrs S. Marsh Mr P. Metcalfe (to December 1993) Dr J.B. Milton (from February 1994) Mr P.W. Morcombe (Newsletter Editor) Dr C.M. Oldham (from February 1994) Dr G.J. Sawyer (from November 1993, co-opted member until then) Dr J. Stanton (to March 1994) Dr B.E. Warren (Convenor, Producer Contact Sub-committee) Mr R.B. Young Mr M. Sanders (from March 1994) PAST PRESIDENTS OF THE SOCIETY M.C. Franklin D.S. Wishart T.K. Ewer H.J. Lee Helen Newton Turner R.H. Watson N.T.M. Yeates G.I. Alexander F.H.W. Morley I.W. McDonald C.H.S. Dolling N.M. Tulloh J.H. Shepherd D.J. Minson J.L. Corbett W.J. Pryor G.E. Robards J.C. Radcliffe A.R. Egan 1954-55 1956-57 1958-60 1960-62 1962-64 1964-66 1966-68 1968-70 1970-72 1972-74 1974-76 1976-78 1978-80 1980-82 1982-84 1984-86 1986-88 1988-90 1990-92 Armidale Melbourne Brisbane Adelaide Sydney Melbourne Armidale Brisbane Canberra Sydney Adelaide Melbourne Perth Brisbane Armidale Canberra Sydney Adelaide Melbourne HONORARY MEMBERSHIP OF THE AUSTRALIAN SOCIETY OF ANIMAL PRODUCTION CHRISTOPHER JOHN THWAITES John Thwaites has had a long involvement with the Australian Society of Animal Production. He has been a committee member of the New England branch most years since 1970, including several terms as Treasurer, two as Vice-President and one as President. ` has consistently contributed much to the He continuing liveliness of the New England branch, activities which have helped increase regard among livestock producers for The University of New England, for the excellence of the contributions to the development of the industry. His professional activities have benefited communities both locally and internationally such as from his involvement with New South Wales agriculture and farm management courses in various appointments such as consultant, adviser, examiner and editor. The assistance he gives voluntarily to students from overseas in all Faculties of The University of New England to help them adapt to a new and strange environment has been particularly appreciated. In 1982 to 1984 John was Federal Secretary of the Society in which he not only dealt with the large and varied burden of work with great efficiency but improved procedures in dealing with the Society' s business. Since that time he has continued as Publications Officer with the Federal Council, implementing a highly effective system for sales and distribution of Proceedings that has been used by successive Federal Councils. With sales of Proceedings to over 30 countries as well as to local libraries and individuals, the distribution of Proceedings has been an important means of disseminating research findings to our own rural community, providin g useful material for undergraduate and postgraduate teaching and promoting Australian animal production throughout the world. Invisible to the majority of members, his longstandin g contribution to the financial well-being of the Society through the sale of Proceedings has been considerable. For his outstanding service to the New England branch and Federal Council of the Society, the Australian Society of Animal Production is pleased to elect him an Honorary Member. EDMUND WYNDHAM Ed' association with the New England Branch extends over many years, but he has been a s particularly enthusiastic and active member since returning to Armidale in 1979. For many years since, he has been a valuable committee member, providing expertise and ideas and assisting with the organisation of meetings. In addition, he has served a term as Vice-President and two terms as President. In all roles his positive contribution to the Branch has been widely appreciated by members. While Ed has a strong academic background he is also a successful grazier, running his property 'Karuah' to the east of Armidale. He has actively supported research programs on his property, providing facilities and areas for field trials, and has shown particular interest in bridging the gap between scientific advancements and the practical application of these under local conditions. He has a very deep concern for environmental issues, both in the broader arena and in the context of property management. For example, he has been particularly interested in the relationship between tree cover and the performance of breeding ewes. In October 1992 in the course of managing his property, he was knocked from his bike by a passing vehicle and lay in a coma for several months, but fortunately shook off his coma and is now making a steady recovery. He rejoined the committee in July 1993 and is again enthusiastically developing ideas for field days and other activities. For his contribution to animal production and rural affairs in general, and to the New England Branch of the Society in particular, the Australian Society of Animal Production is pleased to enrol him as an Honorary Member. THE FOLLOWING HAVE BEEN AWARDED HONORARY MEMBERSHIP OF THE AUSTRALIAN SOCIETY OF ANIMAL PRODUCTION: Honorary members shall be members who, in the opinion of the Council of the Society, have made outstanding and continued contributions to the welfare and purpose of a Branch or of the Society as a whole. Joseph Phillip Kahler, elected 11 February 1976 Clarence James Daley, elected 20 August 1980 Ian Neville Southey, elected 12 May 1982 John Murray George, elected 10 February 1986 Andley George Ward, elected 16 May 1986 Edward (Ted) Ben Byers, elected 16 May 1988 John Terre11 Williams, elected 16 May 1988 Barry Graham Lukins, elected 10 July 1990 Christopher John Thwaites elected 7 July 1994 Edmund Wyndham elected 7 July 1994 THE FOLLOWING HAVE BEEN AWARDED FELLOWSHIP OF THE AUSTRALIAN SOCIETY OF ANIMAL PRODUCTION: Fellows shall be members who, in the opinion of the Co until of the Society, have rendered eminent service to animal production in general or within A ustralia in particular. 25 January 1956 Charles Euston Young 19 February 1962 Mervin Clarence Franklin Hedley Ralph Marston 11 August 1964 (posthumously) Phillip Gurner Schinckel 23 February 1966 Helen Newton Turner 21 February 1968 Keith Valentine Leighton Kesteven Archibald James Vasey Rodger Henry Watson 17 August 1970 Eric John Underwood David Sutcliffe Wishart 17 February 1972 Hector John Lee George Russell Moule 20 February 1974 Frederick Harold William Morley 11 Februarv 1976 Alan Charles Hassall Lancelot Hamilton Lines Ian Wilbur McDonald Patrick Reginald McMahon 22 February 1978 Albert Henry Bishop Victor Gordon Cole Leslie Alfred Downey Reginald John Moir Robert Love11 Reid Wallace Carl Skelsey Percival James Skerman Dudley Martin Smith Neil Tolmie McRae Yeates 20 August 1980 Graham Ian Alexander Gordon Lee McClymont Terence James Robinson Derek Edward Tribe 12 May 1982 Sydney John Miller Norman McCall Tulloh Henry Greig Turner William Maxwell Willoughby 15 February 1984 William George Allden Robert Henry Hayman James Irwin Faithful1 Maple-Brown Jim Harcourt Shepherd 19 Februarv 1986 George Alexander Charles Hoani Scott Dolling Ian Lind Johnstone Dennis John Minson William Henrv Southcott 16 May 1988 John Lovick Corbett Haydn Lloyd Davies Peter Everard Geytenbeek Geoffrey Roger Pearce Laurence Cecil Snook 10 July 1990 Allan Axelsen James Philip Hogan Trevor William Scott Robert Humphrey Weston 6 July 1992 Michael Freer Hugh McLeod Gordon John Ryves Hawker David Roy Lindsay Mary Esther Rose 7 Jury 1994 Russel William Moubray Hodge Keith Johnston Hutchinson James Patrick Langlands Douglas Barrie Purser John Edward Vercoe vii JOHN EDWARD VERCOE After graduating in Agricultural Science from Melbourne University, John Vercoe worked with the Victorian Department of Agriculture at Werribee and was awarded a M.Agr.Sc.(Hons) for research on feed intake of grazing sheep. He returned to Melbourne University under the supervision of Professor Derek Tribe and was awarded a Ph.D. for his research on the interrelationships between dietary protein and energy in the determination of weight change and wool growth in penned and grazing sheep. His post-doctoral research was with Dr K.L. Blaxter (later Sir Kenneth Blaxter FRS) at the Hannah Research Institute where he investigated the heat increment of dietary formic acid in sheep. This work stimulated a new line of research on compounds that inhibit methane production by competing for hydrogen in the rumen. On appointment to CSIRO in Rockhampton in 1964 he began to study the genetic and non-genetic factors that influence the efficiency of beef production in stressful tropical environments. The widely-held belief that the prime reasons for the differences in growth rate between grazing Bos tawus and Bos in&us (zebu) cattle lay in the superior digestive efficiency of the zebu breeds was soon dispelled. He showed that at least part of the observed advantage of zebus grazing low nitrogen pastures arose from a greater capacity to recycle urea to the rumen. Furthermore he demonstrated that, on low nitrogen roughages, breed and animal differences in plasma urea concentration and urinary urea could be largely accounted for by differences in water intake. Dr Vercoe' investigations led him to study the effect of a range of environmental stressors on the s nitrogen and energy metabolism of different breeds. High ambient temperatures and humidities resulting in elevated rectal temperatures, internal and external parasites and variations in the quantity and quality of the diet were all investigated, and significant genotype by environment interactions were observed which were explained in terms of the effect of the environment on the nutritional physiology of the animal. John Vercoe and his research colleague Dr John Frisch, developed a concept that has influenced the understanding of the origins of genotype-environment interactions and consequently the breeding and management strategies necessary to increase cattle production in tropical and other stressful environments. The core of this concept is the negative correlation between those characters which determine growth potential of a genotype and those which determine its resistance to environmental stressors. Practical breeding programs that avoid trading off improvements in one set of characters at the expense of another are now in place in the northern industry. These studies have contributed significantly to the widespread industry acceptance of the Brahman and its crosses, which contribute to a significant improvement in the productivity of the northern beef herd and has resulted more recently in a major collaborative project with the beef industry to import two African cattle breeds, the Boran and the Tuli. Dr Vercoe was secretary of the Victorian Branch of the Society in the early 60' and a founding s member of the central Queensland sub-branch, and has maintained a keen interest in the affairs of the Society at sub-branch and Federal level. As Assistant Chief of the Division of Tropical Animal Production and Officer-in-Charge of the Tropical Cattle Research Centre for more than a decade, he has had a profound influence on the direction of beef research in northern Australia. His own research has proven the need and the value of interdisciplinary research, and has highlighted the limitations of a single discipline approach to solving industry problems. He is a long-time advocate of the desirability of cooperative research efforts with other organisations and has initiated moves to implement them. For his contributions to animal production, the Australian Society of Animal Production is pleased to enrol him as a Fellow of the Society. Vlll ... JAMES PATRICK LANGLANDS James (Jim) Patric k Langlands B.Sc.(Agric)(Hons), B.Fin.Admin., Ph.D., D.Sc. was born in London in 1937, and graduated with first class honours in agricultural science from Wye College in 1959. He was awarded a postgraduate scholarship to attend the Rowett Research Institute, Aberdeen, Scotland from 1959 to 1962, and to undertake studies on the nutrition and production of grazing animals. He received his Ph.D. from the University of Aberdeen in 1962 for a thesis on energy intake and its utilisation for maintenance by the intensively grazed ruminant. Jim joined the CSIRO Division of Animal Physiology in August 1962, and was located at the Pastoral Research Laboratory, Armidale. At this time CSIRO was restructuring the Pastoral Research Laboratory to undertake studies on the grazed plantOrazing animal complex based on a systems approach under the a direction of W.M. Willoughby and I.W. McDonald. It was a time of prosperity for Australia and the Wool Industry, and CSIRO were able to attract staff from all over the world. It was a stimulating environment and Jim flourished. He produced series of papers on assessing the intake and nutrient status of grazing sheep, the factors which orowth and lamb production, efficiency of wool production and the nutritive affect nutrient requirements, a value of pasture. These studies of sub systems were integrated into whole system studies with emphasis 0 on the implications of varyin, stocking intensity, and their relationship to drought and supplementary feeding, pasture improvement and deterioration, and the nitrogen and phosphorus economies of grazing systems. In 1975 the University of London awarded Jim a DSc. for a thesis based on his published research. In 1976 he was appointed chairman of the Division' mineral program with responsibility for s investigating the mineral needs of animals and satisfying them by supplementation, and investigating the mineral needs of pastures and developing appropriate fertiliser strategies. Staff were located in Armidale, Melbourne, Perth and Sydney, and several products were developed in the program and subsequently marketed both in Australia and overseas. Jim' own research was directed to examining subclinical trace s element deficiencies in grazing livestock, their biology, incidence, identification and correction. This work enhanced the high national and international reputation he had already gained. He has published over SO scientific papers in refereed journals, and has recently retired from the editorial advisory board of the journal Animal Feed Science and Technology. He also served as officer-in-charge of the Pastoral Research Laboratory in the late 1970s and was the first Assistant Chief of the CSIRO Division of Animal Production appointed at Armidale. He has a strong commitment to the application of agricultural science to the pastoral industry and to agribusiness, and holds a commerce degree from the University of New England. He has been a loyal supporter of the New England Branch of the Australian Society of Animal Production for over three decades, and is a past President of the branch. He is a frequent speaker at meetings of the branch and at producer gatherings. For his contributions to animal production and the Society, the Australian Society of Animal Production is pleased to enrol him as a Fellow of the Society. ix RUSSEL WILLIAM MOUBRAY HODGE Russel Hodge completed a Diploma in Agriculture at Longeronong, Victoria in 1952 and the degree course in Agricultural Science at Melbourne University in 1956. He commenced employment with the Department of Agriculture, Victoria, in 1957 and a lifetime involvement followed in improved nutrition, welfare and health of sheep. His early studies involved improved nutrition and helminth control in Border Leicester x Merino ewes grazing irrigated pastures at high stocking rates in Southern Victoria. High productivity resulted when nutrition and helminth controls were adequate. Russel gained a Ph.D. from the University of Melbourne in 1970 comparing the nutritional efficiency of the pre-ruminant lamb with that of the young pig. These studies with liquid diets demonstrated for the first time the tremendous potential of the young lamb and pig for rapid growth and efficient food conversion. In 1971 he undertook postgraduate studies at the Grasslands Research Institute, Hurley, studying new techniques for automated feedin g of liquid diets to lambs, the use of nondegradable lipids in ruminant nutrition and factors influencing the herbage intake of grazing sheep and cattle. In 1972 he returned to the Animal Research Institute in Werribee as Section Leader of the Ruminant Nutrition Group with responsibility for a comprehensive program in nutrition, reproduction and grazing management of sheep and cattle which was to the great benefit of Victoria and southern New South Wales. Russel was involved throughout the scientific community, having spent numerous years on the committee of the Victorian Branch of the Australian Society of Animal Production and the Nutrition Society of Australia. He was an inaugural member of both societies. Russel served with distinction on the sub-committee of the Standing Committee on Agriculture' Animal Production Committee which s developed the most comprehensive set of feeding standards for ruminants in Australia. s, During the 1980' Russel was quick to realise the importance of welfare considerations in animal production. In particular he was involved in the development of multi-discipline teams to study the nutrition and welfare of live sheep in shipment programs to the Middle East. A range of studies involving the simulation of the environment were developed. These involved stocking density, temperature, humidity, pen space allowances and pre-treatment of animals. Identification and removal of ` shyfeeders' and provision of an adequate digestible energy intake were seen to be important. Further studies were then developed on board ships to establish causes of death. Russel Hodge retired from the Department of Agriculture in 1992, having devoted 36 years of continuous service to the improvement of nutrition, welfare and health of Australian livestock. For these contributions, the Australian Society of Animal Production is pleased to enrol him as a Fellow of the Society. KEITH JOHNSTON HUTCHINSON Keith Johnston Hutchinson graduated (B.Sc.Agr.) from the University of Sydney in 1950. He spent the next three years in the Queensland Department of Agriculture as an extension and research officer where he investigated carcase quality in baconer pigs. He received a Master of Agricultural Science from Sydney University in 1955 for this study. Keith was appointed as a lecturer in Animal Husbandry at Roseworthy Agricultural College in 1953 where he taught animal nutrition, physiology and breeding, to both College and University of Adelaide students. Personal research projects at Roseworthy included work in sheep breeding, wool biology and sheep-pasture studies. Keith completed his last 6 months at Roseworthy as Acting Principal of the College. In 1962, Keith joined the CSIRO Division of Animal Physiology at Armidale, NSW and he began research into the impact of fodder conservation on sheep production systems. He studied the interactions between fodder conservation and stocking rate, and in this research he emphasised system processes such as flock intake, feeding efficiency, substitution effects and the elaboration and use of body reserves. His use of the ecological concept of energy flow to interpret the results of this fodder conservation study was pioneering. Keith was one of the few people in the 1970's to make the connection between agriculture and ecology and today, in the 1990' this framework s, forms the basis of the new field of ago-ecology. For these studies into the ecology and energetics of fodder conservation systems, he was awarded a Ph.D. in 1970 and the conclusions from this study continue to form the basis of recommended practice in relation to fodder conservation in Australia. In the 1980' and 1990' Keith extended the concept of energy flow to managed grazing systems. His s s, studies of energy flow and, later, the nutrient dynamics of grazed pastures within the broader context of the whole pasture ecosystem, included not only domestic livestock and pasture plants, but also other consumer and decomposer biota, both invertebrate and microbial. One important aspect of this work was that Keith included the below-ground component of the pasture ecosystem which is often ignored, even today, by agricultural scientists because of the difficulties involved in investigation. Keith' work on the role of biological cyclin g in the phosphorus economy of temperate pastures s demonstrated the importance of nutrient cycling in these systems. By taking the ecological point of view in his research, he filled an important gap in fertiliser research in Australia where emphasis had been placed on physico-chemical and plant responses. From 1979 to 1989 Keith blended administrative duties and research when he was appointed Assistant Chief of the Division of Animal Production. During this time he made significant contributions to research on management and production ecology of grazed pastures. Keith retired from CSIRO in 1991 but stayed on as a Post-Retirement Fellow and is still actively involved in research. His main interest today is in sustainability issues in grazed pastures, particularly as they relate to the resilience and stability of perennial species in improved pastures. One study, extending over 30 years, has provided a unique data set on which to base an analysis of these two important sustainability concepts. Keith is the author or co-author of 80 scientific publications, covering a wide range of disciplines including animal nutrition, agronomy, soil biology and ecosystem ecology. In 1985 he prepared a comprehensive report for the Standing Committee of Agriculture on 'Improving the Nutritive Value of 0 Forage' and also in 1991 reported to the Workin, Party on Sustainable Agriculture on 'Sustainable Grazing Systems' as part of an assessment of ecologically sustainable development. Keith has been a member of the Australian Society of Animal Production for 40 years, he has been a regular contributor to the Society' Biennial Conferences, and was President of the New England Branch in 1992. For his s contributions to the Society and his research on the production ecology of our temperate grazing resource, the Australian Society of Animal Production is pleased to enrol him as a Fellow of the Society. . DOUGLAS BARRIE PURSER Barrie Purser grew up on a wheat and sheep farm in Western Australia and his close affinity with the farming community has been a strong influence throughout his career. He graduated from The University of Western Australia in B.Sc.(Agric.)(Hons), followed by a Ph.D. on the population dynamics of rumen protozoa. In 1961 Barrie took up a position as Research Associate in the Institute of Nutrition and Food Technology, Ohio State University where he established a research program on the amino acid requirements of ruminants, one of the first to include the effect of manipulating the rumen microbial population on the supply of amino acids to the host animal. This was the beginning of a career of highly innovative research with a strong focus on the practical benefits of the research. In 1967 Barrie was appointed as Associate Professor in the Department of Animal Husbandry, Michigan State University where he was coordinator of postgraduate studies. In 1969 he returned to Australia as Principal Research Scientist in the CSIRO Division of Plant Industry in Perth, and later became Senior Principal Research Scientist in the CSIRO Division of Land Resources Management. Here he undertook research on the feeding value of mediterranean pastures, the use of supplements including minerals, and the influence of these on wool production and quality, bringing into sharp focus the relationship between the nutrition of grazing sheep and wool quality. He was appointed as Officer in Charge of the Mineral Research Unit in the CSIRO Division of Animal Production in Perth in 1977, and in 1982 was appointed as Assistant Chief of the Division. Barrie has made outstanding contributions to the advancement of Australian agriculture and, in particular, animal production in mediterranean Australia, through his innovative research, his research leadership, his commitment to postgraduate teaching and his contribution to reviews of research in Australian agriculture. Barrie' philosophy of research, focussed in the framework of farming systems, s has been evident in his research leadership. He has moulded scientists from different disciplinary backgrounds into an integrated research group focussed on wool-producing farm systems in mediterranean Australia. The group has continued to respond positively to the changing needs of Australian agriculture, first in addressing trace mineral nutrition of grazing sheep with appropriate mineral supplements and fertilisers, and more recently in its leadership in research in Australia on the problem of 'tender' wool. Important characteristics of Barrie' research have been his emphasis on excellence in science, the s breadth of his research and his generosity with ideas. They have been key elements in his success in research leadership, as a teacher and as a research manager. Barrie is author of more than 70 scientific papers and book chapters. He has supervised 10 Ph.D. and 8 MSc. students in Australia and the United States. As an advocate of strong links between CSIRO and universities, he encouraged the appointment of academic staff jointly by CSIRO Division of Animal Production and the Universities of Western Australia and New England, and initiated what is now the CRC for Premium Quality Wool. He was a member of the CSIRO/University of Western Australia and CSIRO/Murdoch University Collaborative Research Committees since their inception and served terms as chairman of each committee. Apart from overseas recognition for his work in Australia, he has contributed substantially to Australia' aid programs in developing countries. He was Research Coordinator and Project manager for s the Project for Animal Research and Development at Ciawi, Indonesia, in 1981, and from 1985 to 1990, leader of two ACIAR projects on the nutrition of sheep in northern China. Through his skill as a negotiator he fostered research teams based on collaboration between disparate groups in these countries, and successfully integrated this research and its extension to farmers. Barrie was a foundation member of the Western Australian Branch of the Society and has continued to be active in the affairs of the Society serving as President and Committee member of the Branch, and as a member of Federal Council. For his contributions to animal production and his service to the Society, the Australian Society of Animal Production is pleased to enrol him as a Fellow of the Society. xii THE UNDERWOOD LECTURES In honour of Professor Underwood, O.A., C.B.E., B.Sc.(Agri.)(Hons) W.A., Ph.D.(Cantab.), Hon. D.Rur.Sci.(NE), Hon. D.Sc.(Wis.), Hon. D.Sc.(Agric.) W.A., Hon. D.Sc.(Melb.), F.R.S., F.A.A., F.T.A., F.A.I.A.S., F.A.S.A.P., Hon. F.A.C.V.S. Agricultural Scientist 1905-1980 The Lecturers have been: 1984 1986 1988 1990 1992 1994 R.J. Moir H.J. Lee I.W. McDonald A.D. Robson J. Stocker K.W. Entwistle x111 ... ACKNOWLEDGMENTS The Australian Society of Animal Production gratefully acknowledges the support and financial contributions from the following organisations: Commonwealth Scientific and Industrial Research Organisation Department of Agriculture Western Australia Cattle Industry Compensation Fund Research Advisory Committee Co-operative Research Centre for Legumes in Mediterranean Agriculture Wesfarmers Ltd The University of Western Australia Australian Wool Research and Promotion Organisation Meat Research Corporation MSD AGVET Currie Hall Mr J.C. Roberts and 'The Grange' stud The Society wishes to thank those individuals who have helped to organise the conference and produce the Proceedings. G.J. Sawyer, G Tudor (co-opted members of the editorial committee), M Lalchere, S. Mata, V. McSharer (assistance in preparation of the proceedings) xiv REFEREEING OF PAPERS Four-page papers in this volume were examined by at least two referees in accordance with usual journal standards and are regarded by the Society as full publications. The material is subject to copyright and may not be presented elsewhere without permission of Federal Council. Contract papers have also been refereed, but are regarded as discussion papers. One-page papers were examined by one referee. Both one-page papers and contract papers may be presented elsewhere in expanded form. Invited reviews were examined by members of the Editorial Committee or their nominees. Criteria for acceptance of papers are that material i s of interest to members of the Society, has some novel aspect, is sound and presented in a readable form consistent with instructions to authors. CITATION OF PAPERS Papers in this publication should be cited as appearing in the Proceedings of the Australian Society of Animal Production (abbreviation: Proc. Aust. Sot. Anim. Prod.). It is suggested that individual contributions in Contract Reviews should be cited as follows: SAVAGE, P.H. (1990). In: Whiteley, K.J. 'High Quality Contaminant-Free Wool'. Proc. Aust. Sot. Anim. Prod. 18: 53-61.