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Matching ruminant production systems with available resources in the tropics and sub-tropics
200
Book reviews
exert their influence but not as simple extensions of existing trends. The farm and food system will continue to grow, labour productivity will continue to rise, food processing and distribution will continue to take an increasing share of the food dollar--but all at slower rates than in the past. Export markets for grain, oilseeds and cotton will remain major determinants of national farm profitability but the general tendency for world supplies to run ahead of world demand is unlikely to be reversed and prospects for growth in profitable markets do not look favourable. The text is very readable and balanced. The author has drawn successfully on current extension material and specialist reports to produce an up-todate analysis of US agricultural futures. This relatively short book, with its good bibliography and index, should be of interest to policy-makers, teachers and students throughout North America and beyond.
N. 13. Lilwall Matching Ruminant Production Systems with Available Resources in the Tropics and Sub-Tropics. T. R. Preston & R. A. Leng. Renambul Books, Armidale, NSW, 1987. ISBN 0-9588290-12. This book has taken a long and bumpy ride to the press: starting as the material of a course of lectures sponsored by ILCA, encountering some critical opposition and delays, leading eventually to private publication by the authors. Preston and Leng both stimulate and irritate with their insights into ruminant nutrition, their obsessions, strengths and weaknesses. While the book is a tribute to their courage in promulgating their vision, it is strangely uneven and dogmatic. Introductory chapters usefully lay out a strategy for the development of livestock systems in the context of appropriate technology. Following chapters cover digestive physiology, metabolism and feeding of ruminants in varying degrees of detail. The remaining half of the book deals with feeding systems, with emphasis on utilization of fibrous crop residues and on coping with inadequacies in pastoral systems. The book is thus a mixture of the biochemistry of animal nutrition and animal husbandry techniques and extension advice, and attempts to interrelate these to provide a basis for better resource utilization in tropical and sub-tropical farming systems. Somehow the synthesis fails to work, perhaps the book is attempting to unite two very disparate subjects: ruminant biochemistry and the socioeconomic and climatic constraints on farming systems. On the former, the treatment is selective in the level of detail presented, and the content is sometimes controversial. The chapter on intake, for example, contains a mass of detail, much of it unqualified, which fails to cohere in a balanced treatment. This is unhelpful to the non-specialist
Book reviews
201
and will frustrate the specialist. The aims of the book are laudable; the authors clearly empathize with the problems which beset farmers in developing countries, and much of the work reported is a tribute to the authors' energetic pursuit of their goal. Yet the idiosyncracies of the book give the impression, ironically, that the authors have written it for themselves. A. W. lllins
Extension Science: Information Systems in Agricultural Development. By Niels Rfling. Cambridge University Press, Cambridge, 1988. 233 pp. Price: £35.00, US$34.50 hardback; £11.95 paperback. This volume, in the series 'Wye Studies in Agricultural and Rural Development', is an English language second edition of a Dutch text published in 1983. Most of the chapters are based on, or extensions of, other published material. The author notes that extension is 'an instrument of deliberate intervention to achieve the intervener's goals, which can only be effective by inducing voluntary change and hence by satisfying the client's goals'. Resolving this contradiction is far from simple, and the book has important lessons for everyone involved in the development process. The first chapter presents short illustrations of various aspects of extension in a practical setting, while chapter 2 provides an overview of the development of extension science, culminating in the concept of an information system. In chapter 3, the mechanism of extension is considered as a tool for inducing voluntary change. The three following chapters deal with aspects of targetting: methods for identifying homogeneous target categories of farmers, arguments for and against the notion that extension should be aimed at progressive farmers, and a case study in central Kenya. Having identified appropriate customers, another important consideration is the problem of how 'to create active utiliser systems' (farmer participatory organisations), the subject of chapter 7. The final chapter considers the agricultural information system as a tool for the design and analysis of research and extension. Extension science seems to have developed its own jargon, and this does not always make for easy reading for the non-specialist. And it is odd, on page 80, in a rare excursion into figures, to describe a patently skewed distribution as normal. The editing of the final section of chapter 8 would appear to have been done in a hurry. These are minor quibbles only. There is a great deal to commend the book, and it must be hoped that it reaches the wide and diverse audience intended by its author. P. K. Thornton
Book reviews
exert their influence but not as simple extensions of existing trends. The farm and food system will continue to grow, labour productivity will continue to rise, food processing and distribution will continue to take an increasing share of the food dollar--but all at slower rates than in the past. Export markets for grain, oilseeds and cotton will remain major determinants of national farm profitability but the general tendency for world supplies to run ahead of world demand is unlikely to be reversed and prospects for growth in profitable markets do not look favourable. The text is very readable and balanced. The author has drawn successfully on current extension material and specialist reports to produce an up-todate analysis of US agricultural futures. This relatively short book, with its good bibliography and index, should be of interest to policy-makers, teachers and students throughout North America and beyond.
N. 13. Lilwall Matching Ruminant Production Systems with Available Resources in the Tropics and Sub-Tropics. T. R. Preston & R. A. Leng. Renambul Books, Armidale, NSW, 1987. ISBN 0-9588290-12. This book has taken a long and bumpy ride to the press: starting as the material of a course of lectures sponsored by ILCA, encountering some critical opposition and delays, leading eventually to private publication by the authors. Preston and Leng both stimulate and irritate with their insights into ruminant nutrition, their obsessions, strengths and weaknesses. While the book is a tribute to their courage in promulgating their vision, it is strangely uneven and dogmatic. Introductory chapters usefully lay out a strategy for the development of livestock systems in the context of appropriate technology. Following chapters cover digestive physiology, metabolism and feeding of ruminants in varying degrees of detail. The remaining half of the book deals with feeding systems, with emphasis on utilization of fibrous crop residues and on coping with inadequacies in pastoral systems. The book is thus a mixture of the biochemistry of animal nutrition and animal husbandry techniques and extension advice, and attempts to interrelate these to provide a basis for better resource utilization in tropical and sub-tropical farming systems. Somehow the synthesis fails to work, perhaps the book is attempting to unite two very disparate subjects: ruminant biochemistry and the socioeconomic and climatic constraints on farming systems. On the former, the treatment is selective in the level of detail presented, and the content is sometimes controversial. The chapter on intake, for example, contains a mass of detail, much of it unqualified, which fails to cohere in a balanced treatment. This is unhelpful to the non-specialist
Book reviews
201
and will frustrate the specialist. The aims of the book are laudable; the authors clearly empathize with the problems which beset farmers in developing countries, and much of the work reported is a tribute to the authors' energetic pursuit of their goal. Yet the idiosyncracies of the book give the impression, ironically, that the authors have written it for themselves. A. W. lllins
Extension Science: Information Systems in Agricultural Development. By Niels Rfling. Cambridge University Press, Cambridge, 1988. 233 pp. Price: £35.00, US$34.50 hardback; £11.95 paperback. This volume, in the series 'Wye Studies in Agricultural and Rural Development', is an English language second edition of a Dutch text published in 1983. Most of the chapters are based on, or extensions of, other published material. The author notes that extension is 'an instrument of deliberate intervention to achieve the intervener's goals, which can only be effective by inducing voluntary change and hence by satisfying the client's goals'. Resolving this contradiction is far from simple, and the book has important lessons for everyone involved in the development process. The first chapter presents short illustrations of various aspects of extension in a practical setting, while chapter 2 provides an overview of the development of extension science, culminating in the concept of an information system. In chapter 3, the mechanism of extension is considered as a tool for inducing voluntary change. The three following chapters deal with aspects of targetting: methods for identifying homogeneous target categories of farmers, arguments for and against the notion that extension should be aimed at progressive farmers, and a case study in central Kenya. Having identified appropriate customers, another important consideration is the problem of how 'to create active utiliser systems' (farmer participatory organisations), the subject of chapter 7. The final chapter considers the agricultural information system as a tool for the design and analysis of research and extension. Extension science seems to have developed its own jargon, and this does not always make for easy reading for the non-specialist. And it is odd, on page 80, in a rare excursion into figures, to describe a patently skewed distribution as normal. The editing of the final section of chapter 8 would appear to have been done in a hurry. These are minor quibbles only. There is a great deal to commend the book, and it must be hoped that it reaches the wide and diverse audience intended by its author. P. K. Thornton