In trying to write this preface we have had many frustrating efforts. What did we want to say in a preface and what message should it provide? We know our work is controversial, we recognise that by nature we both extrapolate and our critics may claim we have gone too far.

The book is a statement and is meant to stimulate, even direct, research into areas we feel are relevant and important. The approach we have taken, has much to do with our personal backgrounds and experience. Both of us spent our youth in agriculture. We were both motivated to go to university to train in agriculture with a view to taking up farming as a career. We both soon recognised this was not our vocation and we were stimulated to develop a depth of appreciation of the biological sciences. It was therefore rational to proceed to higher degree studies. For one of us the objective was to obtain sufficient training to develop technologies to improve the lot of the farmer; the other was to develop understanding ofthe quantitative roles of nutrients and to bring this knowledge to bear on production problems. At about the same age, both of us undertook projects in development as we saw this as an opportunity to apply what we had learned. Both of us applied what we knew without adaptation and were initially unsuccessful. Remarkably, both our careers in development began examining the utilisation of molasses (as a production feed in Cuba and as a drought feed in India). Since that time, many aspects of our work have overlapped, have been mutually stimulating and beneficial and we formed a partnership which allowed one to concentrate more on the basic nutritional knowledge whilst the other then was able to give a greater priority to broader issues of development and application.

The experience we have gained from our collaborative efforts in many developing countries has convinced us about a number of issues, which we discuss in the book.

We give evidence for what we consider inappropriate approaches. These include for example:

• Feeding standards which are based on measurements of what is excreted from the animal in waste product

• The "Black Box" (eg. least cost formulationS') approach which provides answers to specific questions, but does not permit, or encourage the technician to understand, why and how events take place in the animal

• The training of students from developing countries in discipline-orientated animal production packages that do not take into account the socio-economic constraints to development.

We strongly support:

• Policies which lead to the establishment of guidelines on which to base feeding practices; where the emphasis is on understanding how the rumen microorganisms, and the animal, use nutrients and substrates for productive purposes

• Collaboration between institutions and individuals from developing and developed countries, in the fields ofresearch and teaching. Fundamental to this is the deployment of international and bilateral aid to further such endeavours, the final aim of which is increased "self-reliance" rather than "dependence"

• Integration - of farming systems and scientific disciplines

• Ecological principles and the belief in the capacity of plants to satisfy world needs for food and fuel, though a strategy which generates, rather than curtails, employment.

Neither of us are afraid to be controversial and we saw no value in a book that simply reviewed the literature. We have attempted to sort out the important from the trivia and have attempted to put knowledge into frameworks that can be relatively easily assimilated. The book is intended to be a reference used with other suitable texts by graduates to assist in their appreciation of the variables that apply to animal production in the real world, outside of the research laboratory.

The "Pre-testing" edition

Parts of this book have already appeared in a pre-testing preliminary form printed by the International Livestock Centre for Africa (ILCA).

The idea of producing this book has been with us for a number of years; the stimulus to start writing arose when we were asked by the then Director General of ILCA, Dr. P. Brumby to present (and later to write up) a short course on animal nutrition for students from a number of African countries. This version was originally intended to meet the needs of that course and to provide a recipe book for appropriate research technology. It was aimed at young research workers with limited facilities. We were encouraged and supported to come together to write in both Armidale and in Addis Ababa for which we are truly grateful. The book, however, developed beyond its original intended scope and ICLA decided to limit its publication to the Pre-testing edition. We have now developed the concepts and approaches more extensively and have re-written a considerable proportion of the original edition. The views expressed are solely our own.