New Concepts of Cattle Growth
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NEW CONCEPTS OF CATTLE GROWTH Roy T. Berg Rex M. Butterfield Foreword by St C. S. Taylor SYDNEY UNIVERSITY PRESS NEW CONCEPTS OF CATTLE GROWTH Roy T. Berg Rex M. Butterfield Original Publisher SYDNEY UNIVERSITY PRESS University of Sydney 1976, ISBN 0 424 00002 4 Now Published by The Internet-First University Press This manuscript is among the initial offerings being published as part of a new approach to scholarly publishing. The manuscript is freely available from the Internet-First University Press repository within DSpace at Cornell University at http://dspace.library.cornell.edu/handle/1813/62 The online version of this work is available on an open access basis, without fees or restrictions on personal use. A professionally printed version may be purchased through Cornell Business Services by contacting: [email protected] All mass reproduction, even for educational or not-for-profit use, requires permission and license. For more information, please contact [email protected]. We will provide a downloadable version of this document from the Internet-First University Press. Ithaca, NY March 2005 SYDNEY UNIVERSITY PRESS Press Building, University of Sydney UNITED KINGDOM, EUROPE, MIDDLE EAST, AFRICA, CARIBBEAN Prentice/Hall International, International Book Distributors Ltd Hemel Hempstead, England National Library of Australia Cataloguing-in-Publication data Berg, Roy Torgny New concepts of cattle growth/ [by] Roy T. Berg [and] Rex M. Butterfield.—Sydney: Sydney University Press, 1976. Index. Bibliography. ISBN 0 424 00002 4. 1. Cattle—Physiology. I. Butterfield, Rex Milton, joint author. II. Title. 636.208 First published 1976 © Roy T. Berg and Rex M. Butterfield 1976 This book is funded by money from THE ELEANOR SOPHIA WOOD BEQUEST Printed in Australia by Macarthur Press, Parramatta CONTENTS FOREWORD Vll PREFACE ix 1 Cattle growth and beef production 1 2 Growth patterns of muscle, fat and bone 13 3 Changes in the chemical composition of cattle during growth 44 4 Muscle growth patterns in steers 65 5 Factors affecting muscle growth patterns 99 6 Fat: its growth and distribution in cattle 143 7 The growth of muscle of cattle relative to that of other species 176 8 Methods of measuring and predicting carcass composition 201 REFERENCES 227 INDEX 235 FOREWORD Animal growth is a vast subject. In its present stage of rapid development, a severe limitation of subject matter is essential for clear presentation in one volume. Contained within this book is a very direct and well integrated account of the growth of fat, muscle and bone, in which patterns of growth, changes in chemical composi- tion, muscle weight distributions, and the influence of nutrition, breed and sex are all clearly and vigorously described. Throughout the 7,000 years that cattle have been part of man's social development, their growth has remained largely a mystery. Significant experimental studies concerned with beef production began possibly about fifty years ago. The results that have accumulated since then—many of them contributed by the authors themselves—have now been brought together in this book, making it an excellent source of factual information and reference. The book is predominantly about cattle. The section on muscle growth, however, includes new results on several other species, and many of the conclusions and ideas discussed are of considerable relevance to animal growth generally. It is a privilege to write this brief foreword and I take the opportunity of expressing open appreciation of the authors' rare blend of enthusiasm and dedication which has produced a very useful, vivid, absorbing and 'meaty' description of growth that will greatly aid and stimulate the continuing development towards more knowledge and perhaps more production also. ARC Animal Breeding Research Organization, ST C. S. TAYLOR Edinburgh PREFACE Growth is a fascinating process. Understanding its intricacies has been the quest of many scientists and laymen alike. An animal starting from a single fertilized egg, through division and differentiation, grows and develops into a complex unit, capable of carrying out all of life's functions—obtaining and utilizing food, surviving nature's stresses and reproducing to continue the species. Animals in their adaptation to particular conditions of life have developed a form and function uniquely suited to survival and reproduction under the natural conditions to which the species has been exposed during its evolution. Man, first as a hunter then as a herdsman, has utilized animals as a source of food. As a herdsman—more specifically as a breeder—man has attempted to mould the form of domestic animals better to satisfy his wants for a more desirable food product. In so doing he may have impinged on the functional characteristics developed over centuries of natural selection. A study of growth in any domestic species must include consideration of the implications of altering form and com- position on functional efficiency. It is our hope in this book, in elucidating a few of the intricacies of growth and of its possible control and direction toward utilitarian goals, also to present guidelines by which functional efficiency may be retained. Beef is produced by the growth of body tissues of cattle. An understanding of how cattle grow may lead to methods for manipulation of the process toward improved efficiency or a more desirable product. Beef is a commodity which is sought by consumers, not because they are conscious of its protein content, or of any special food value, but because it has particular eating qualities. The demand for beef is rising in many countries of the World as the level of disposable income rises. There seems to be every indication that as long as consumers can afford beef they will continue to eat it. In manipulation of the growth process in cattle toward goals of greater efficiency, we must be cognizant of the character of beef which makes it desirable to consumers and this basic character must be retained. There may be a fair degree of leeway in altering carcass composition without affecting the basic characteristics of beef, for IX X PREFACE there is currently a wide range of carcass types which are each regarded as optimum in various parts of the World. Cultural traditions, habits and personal tastes affect the kind of beef consumers seek. The amount and distribution of fat influence the desirability of beef but this varies for different countries and cultures. Where some fat is desired there is often a roughly defined optimum, levels in excess of which render the product less acceptable. Excess fat also affects the yields of saleable beef sought by the butchering trade as it often represents a trimming loss in processing. Amount of fat desired in a carcass may evolve to a fairly critical optimum dictated by a balance between trimming losses to the butcher and eating satisfaction to the consumer. All adult cattle produce beef of some type at slaughter irrespective of their classifications as 'beef, 'dairy' or 'draft' animals; irrespective of age, sex or fatness. Hence the beef produced is a highly variable product, according to how these many factors affect the process of growth of the muscle, fat and bone, which are the three major tissues of beef, and how they affect the particular qualities of the two edible tissues, muscle and fat. It is entirely possible that the great demand for beef is in part related to the variety of the product as influenced by age, sex and fatness as well as by the variety which results from preparation of distinctive products from different parts of the carcass. Many of the changes which people would like to see in beef cattle are unlikely to be achieved. As Vaughan (1939) said, 'the beef calf is "born wrong" from a beef standpoint and no known method of feeding and management can correct its deficiency'. What we must realize is that the animal body, be it cattle or horse or giraffe, has evolved to grow in such a manner that it is functionally efficient. As Goss (1964) put it: 'Since structures without function persist during evolution only at the risk of reducing an organism's general efficiency, there is little chance that mechanisms of growth regulation which are independent of functional considerations would have sufficient selective advantage to survive'. Of course, we can thwart the normal evolutionary changes which are aimed at the maintenance of functional efficiency, and by artificial selection we can perpetuate some most inefficient monstrosities, such as is the peculiar delight of the dog fanciers in many breeds. However, this perpetuation of a functionally inefficient animal seems to have little place in the cattle industry, the survival of which as a producer of beef within the economic reach of sufficient consumers is surely linked PREFACE XI with animals which are adapted to the conversion of inexpensive feeds into muscle. There may be a place for specialized production from such immobile genetic deviants as the 'Culard' or double-muscled animal to supply a special high-priced market, just as there is a place for limited numbers of animals with a tendency to become grossly overfat. However, these should not distract us from the mainstream of beef production which will come from animals capable of harvesting the cheaper feeds. Such a role will not be possible if our animals do not retain a functionally efficient body capable of considerable mobility and also capable of calving unaided on open range. Changes in body composition towards what has been accepted as 'meat-type' conformation of the last few decades have undoubtedly increased the problems of calving. The extreme again is the 'Culard' where hysterotomy (Caesarian Section) is necessary in all births, at least in some breeds. Such a procedure may be justified for the production of sires used for a terminal cross, but it will have little place in the normal scene of cattle production.