PUBLICATIONS IN THE ~MsGRAW-HILL AGRICULTURAL SCIENCES R. A. BRINK, Consulting Editor BREEDING AND IMPROVEMENT OF FARM ANIMALS McGRA W-HILL PUBLICATIONS IN-THE AGRICULTURAL SCIENCES R. A. BRINK, CONSULTING EDITOR ADRIA:\"CE AND BRISON' Propagation of Horticultural Plants AHLGRE);J . Forage Crops Al'iDERi'\O:-O . Dis('ases of Fruit Crops BROWN' Cotton CARROLL AND KRIDER' Swine Production CRUESS' Commercial Fruit and V('getable Products DICKSON . Dis('ases of Field Crops ECKLES, Cm.ms, AND MACY . Milk andl'Iilk Products ELLIKER . Practical Dairy Bacteriology FERXALD AND SHEPARD' Applied Entomology GARD'NER, BRADFORD, AND HOOKER' The Fu~I::lIll('ntals of Fruit Production' GUSTAFSOX . Conservation of the Soil GCSTAFSOX . Soils and Soil Management HAYES, IMMER, A;I;D S:lHTH . Methods of Plant Brf'cdin!( HEALD' Manual of Plant Discases HEALD' Introduction to Plant Pathology HERRINGTO!'l . Milk and Milk Processing HUTT' Genetics of the Fowl JE!'INY . Fact.ors of Soil Formation JULL' Poultry Husbandry LAURIE AND RIES . Floriculture LEACH' Insect Transmission of Plant Dis('ases' MAYNARD' Animal Nutrition :\iETCALF, FLI;I;T, AXD METCALF' Destructiv(' and Useful Insects XEVEXS . Principles of Milk Production PATgRSON . Statistical Technique in Agricultural Research PETERS AND GRt':lnlER . Livestock Production RATHER AND HARRISON' Field Crops RICE AND ANDREWS' Bre('ding and Improvl'mcnt of Farm Animal8 ROADHOUSE AND HEXDERSO!'l . The l\iarket-milk Industry ROBBINS, CRAFTS, AND RAYNOR' \V('('d Control RCHILLETTER AND RICHEY' Textbook of Gl?npra],!'F~lifmTl' STEIXHAUS . Principles of Insect PathologJ1 .,~~ •• Tno;'\IPsoN . Soils and Soil Fertility '. THO~!p'SON . Veg('table Crops WALKER' Diseases of Veg('table C~ops WALKEll . Plant Pathology . WILSO!'l . Grain Crops WOLFE AXD KIl'PS . Production of Fidd Crops The late Leon J. Cole was Consulting Editor of this series from 1937 to 1948. Th('re are also the relatcd scries of McGraw-Hill Publications in the Botanical Science~, of which Edmund W. Sinnott is Consulting Editor, arid in the Zoological Sci~ces, of which Edgar J. Boell is Consulting Editor. Titl('s in the Agricultural Scien!es were publishrd in these series in the period 1917 to 1937, Breeding and lInprovemellt of Farm Animals, VICTOR ARTHUR RICE ,. Professor oj'Animal llusbandry Cni11ersily of ll.fassachusetts AND FREDERICK NEWCOMB ANDREWS , / Professor of Animal Husbandry Pllrdue University With Chapter on Selection in Meal Anirn.o,ls BY EVERETT JAMES WARWICK Geneticist, Bureau of Animal Industry, U.S. Department of Agriculture and Professor of Animal Husbandry, University oJ Tennessee l .\.PAU C~l~"" U ••••~ t i,-13~ Acet M.l Vate: If .I·~ .... ' NEW YORK TORONTO LONDON McGRAW-HILL BOOK' COMPANY, INC. 1951 BREEDING AND IMPROVEMENT OF FARM ANIMALS Olpyright, Hl26, 1934, 1942,1951, by thEl McGraw-Hill Book Company, Inc. Copyright renewed 1954 by Victor Arthur Rice. Printed in the United Htates of America. All rights reserved. This book, or parts thereof, may not be reproduced in any form without permission of the publishers. PREFACE TO THE FOURTH EDITION In the Preface to the First Edition, published in 1926, we said, "This book has been written primarily for use as a textbook of animal breeding. It treats the subject of breeding practice from the scientific standpoint in so far as this is possible at the present time. Breeding is an art to be learned only by practice, but knowledge of principles supplies the only firm foundation for its practice. Superior animals will be more numerous when breeders know why as well. as how." Part of the Preface to the Second Edition, published in 1934, reads, "Great progress has been made in all three of the fields included in the scope of this book since its publication in 1926. In the field of reproduc tive physiology significant discoveries have been made in matters pertain ing to the endocrine control of sex manifestations as well as in those dealing with the maintenance of genital health and normal activity. Great forward strides have been made also in the science of genetics and new phases of this subject have been developed. These include among others the artificial induction of mutations by radiation or heat; the development of the theory of genic balance; and the cytological demon stration of crossing over. The mechanism of transmission is now pretty thoroughly understood and the chromosomal interpretation of inheritance established beyond reasonable doubt. Of great significance, also, are the new approaches and points of view that have come to the fore in the art of breeding. Rules of thumb are fast passing into the discard and breeders are now basing their operations on sound physiological and genetic principles. " The Preface to the Third Edition, published in 1942, is included in full on the following pages. In the present revision, the basic organization remains as it has been from the start, viz., (1) a general introductory section, followed by sec tions dealing with (2) reproductive physiology, (3) genetics, and (4) selection. During the past eight years, significant advances have been made in all these fields: a broadened recognition of the fundamental aspects of animal agriculture together with breed advancements, and shifting emphasis among the various classes of livestock as indicated in Section I, Animals and Man Up to the Present; further unraveling of the intricate interactions of the hormonal regulation of sex manifestations ane! tlJ.e widespread use of artificial insemination as portrayed in Section v ~-.- -- Vl PREFACE TO l'HE FOURTH EDl'l'ION II, Mechanisms of Reproduction; continuing delineation and refinement of the basic l.aws of inheritance and their application to livestock improve ment as shO\m in Section III, Mechanisms of Heredity; and a concerted experimental attack on the problems and implications of the various systems of breeding as related to the main f.unction of animal breeding more successful selection as demonstrated in Section IV, The Art of Breeding. For ultimate success in creating more .efficient and beautiful animals, one must possess an understanding of the basic principles underlying reproductive physiology and inheritance and then gather, interpret, and apply performance facts about his animals so that the hereditary deter miners for desirable qualities may sluwly but surely replace those for undesirable qualities now present in the germ cells of the animals cur rently constituting his herd or flock. It is the authors' hope that this book may provide both the knowledge and the inspiration to accomplish this most worth-while and interesting task. We are again indebted to many friends, authors, and publishers for kindly criticisms, helpful suggestions, and permission to quote and to reproduce illustrative materials. We are happy to acknowledge our special indebtedness for helpful suggestions to Doctors B. B. Bohren and A. E. Bell and Professor R. B. Cooley of Purdue University; Dr. W. A. Craft of the Regional Swine Breeding Laboratory; Doctors J. E. Nordby and C. E. Terrill of the Regional Sheep Breeding Laboratory; and to Professor \V. A. Cowan of the University of Massachusetts. Our very deep appreciation is hereby extended to Dr. E. J. Warwick for his generous and penetrating suggestions throughout our labors and for his willingness to contribute the chapter on selection in meat animals. For invaluable clerical assistance, we wish to thank Mrs. O. R. Rudde forth and Mrs. W. A. Cowan of Amherst, Massachusetts, and Mrs. Thelma Boesch of Lafayette, Indiana. We shall always welcome constructive criticism. VICTOR ARTHUR RICE .FREDERICK NEWCOMB ANDREWS AMHERST, MASS. LAFAYETTE, IND. October, 1950 PREFACE TO THE THIRD EDITION In the early history of the Land Grant Colleges there was an almost complete lack of technical agricultural science supported by experi mental data, with the result that curriculums ·were built largely out of liberal arts materials. Today ,ve have reached the other extreme with so much well-supported technical agricultural science data available that the student of agriculture has all too little time for liberal or cultural courses. Most agricultural students probably get a smattering of repro ductive physiology in general courses in anatomy and physiology and a smattering of genetics in general courses in biology; but since the limita tions of time so often prevent the inclusion of separate courses in repro ductive physiology, animal hygiene, genetics, embryology, etc., and since the inclusion of all these courses would exclude just so many more cultural courses, the author has proceeded on the basis that undergraduate students in animal husbandry should have one complete course in animal breeding with reproductive physiology, genetics, and the art of breeding brought together into one complete whole. He has also endeavored to make this something more than just a technical book on breeding by giving a bit of the historical background involved and by indicating some of the broader implications of the place of man and his animals on this planet; but he has tried to leave to the reader the matter of drawing philosophical deductions. This book is comprised of four sections. Section I begins with the present status of animal breeding and then traces it back to its probable beginnings. The origins of both man and his animals are investigated, as well as the broader aspects of the evolutionary process that apparently brought both into existence. Section II deals with the processes involved in the physiology of reproduction both from the scientific and the practical angle. The breeder should be acquainted with the normal functioning of the genital systems in order that his herds and flocks may be maintained at a high level of reproductive efficiency. Section III is devoted to a study of the principles of heredity. The various types of behavior of the chromosomes and genes, passed on to each new individual by means of the germ cells of its parents, in the perpetuation of ancestral traits or the creation of variations from the older :patterns, are considered in some detail. Although the direct manif"stations of many of these principl~s which are explicitly detailed vii Vl11 PREFACE TO THE THIRD EDITION in lower organisms are difficult or impossible of exemplification in the higher species, it is a VIrtual certainty that they are at work. Therefore a full understanding of the basic principles is necessary if the breeder is to handle, in the most intelligent and profitable manner, his practical problems of selection. Section IV is devoted to what is often called the art of breeding, which may be summed up in one word selection. This term has both a present and a future connotation, since a breeder is constantly selecting from among the best animals making up his herd or flock on the basis of their pedigrees and performance, and he is also anticipating future selection by planning matings to create new animals of a preconceived pattern. Selection, therefore, involves the various systems of breeding both among related and unrelated individuals. In the final chapter the reader can glance backward over the trail that animal breeders and scientists have blazed and look forward to try to foresee" the shape of things to come." It is the author's hope that this book will be stimulating and helpful to students of breeding both in classrooms and on livestock farms. Many friends have assisted the author in the preparation of this book; among them Drs. H. H. Plough and Charles L. Sherman of Amherst Col lege; Dr. Harry L. Shapiro of the American Museum of Natural History, New York; Mr. Bradford Knapp, Jr., of the Bureau of Animal Industry, Washington, D.C.; and Drs. G. Chester Crampton, Johr. B. Lentz, Frank H. Hays and Mr. Floyd Johnson of the }\Iassachusetts State Col lege. Special thanks are due Dr. F. N. Andrews of Purdue Cniversity, Dr. Arthur B. Chapman of the University of Wisconsin, and Drs. Hugh C. "McPhee, Ralph W. Phillips, and Ralph G. Schott of the Bureau of Animal Industry, Washington, D.C., for their suggestions and construc tive criticisms. The author is also greatly indebted to Mr. Talcott Edminister for assistance in reading proof, and to Miss Evelyn Day, who in some ingenious manner deciphered the original manuscript and put it through a typewriter. The author is indebted to Prof. R. A. Fisher and to Messrs. Oliver & Boyd, of Edinburgh, for permission to reprint Tables 29 and 31 from their • book Statistical Methods for Research Workers, 8th edition (1941). Grateful acknowledgment is also made to various authors and pub lishers for permission to use certain of their materials. If the reader is curious as to the sources of the ideas herein expressed, he may discover them.in great measure through consulting the refer enees listed at the close of each chapter. VICTOR ARTHUR RICE AMHERST, MASS. March,1942 CONTENTS PREFACE TO THE FOURTH EDITION . v PREFACE.TO THE THIRD EDITION .. YI SECTION I. ANIMALS AND MAN UP TO THE PRESENT I. Animal Breeding-Pres~nt and Past. . . 1 II. Early Man and Animal Domestication 38 III. Animal Origins and ProgreslSion. . . . . 68 SECTION II. MECHA~ISMS OF REPRODUCTION IY. The Male's Part in Reproduction. . 98 Y. The Female's Part in Reproduction. 134 VI. Reproductive Efficiency. . . . 173 VII. Lowered Fertility and Sterility. . . 198 VIII. Pregnancy and Parturition. . . . . 226 IX. :Mammary Development and the Initiation of Lactation. 249 X. Artificial Insemination. . . . . . . . . . . . . . .. 260 SECTION III. MECHA~ISMS OF HEREDITY XI. History and Problems of Genetics. . . 290 XII. The Principles of Heredity. . . . . . 304 XIII. The Principles of Heredity-(Continued) 339 XIV. The Principles of Heredity (Continued) 364 XV. The Principles of Variation ..... 390 XVI. The Principles of Variation (Continued) . 418 XVII. Sex Determination . . . . . . . . . . 433 SECTION IV. THE ART O}" BREEDING XVIII. Systems of Breeding-Unrelated AniRlals . 452 XIX. Systems of Breeding-Related AnimaJs . 485 XX. General Considerations in Selection. .528 ix x CONTENTS XXI. Selection in Dairy Cattle . 580 XXII. Selection in Meat Animals. 644 XXIII. Selection in Horses . . . 708 XXIV. Retrospect and Prospect. . 736 ApPENDIX. Livestock Record Associations . 757 NAME INDEX .. 761 SUBJECT INDEX. 767