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FARMERS BULLETIN - 1 1 67 
 
 UNITED STATES DEPARTMENT OF AGRICULTURE 
 
 ^f|^kT^T r T A T 
 
 SENTIAL 
 
 I 
 
 afcfri:^ 
 
 8 
 
rpHIS BULLETIN is written in simple language for 
 -*- the man who breeds farm animals, who wants to 
 learn the rudiments of the science of breeding, and 
 how to apply them in practice. It sets forth some 
 of the known facts regarding the operation of 
 the forces of heredity. Controversial subjects are 
 avoided so far as possible. 
 
 The reader who cares to go deeper into the study 
 of genetics is referred to textbooks on the subject, 
 and particularly to Department Bulletin No. 905, 
 " Principles of Livestock Breeding," by Sewall 
 Wright. It is published by the U. S. Department 
 of Agriculture, and is obtainable from the Superin- 
 tendent of Documents, Government Printing Office, 
 Washington, D. G., for 15 cents. 
 
 Contribution from the Bureau of Animal Industry 
 
 JOHN R. MOHLER, Chief 
 Washington, D. C. November, 1920 
 
 
ESSENTIALS OF ANIMAL BREEDING. 
 
 GEORGE M. ROMMEL, 
 Chief, Animal Husbandry Division, 
 
 CONTENTS. 
 
 Basic facts about heredity 
 
 The science of breeding 
 
 The unit of life 
 
 The beginnings of life 
 
 The gestation period 
 
 Incubation period in birds. 
 
 Determination of sex 
 
 Fecundity 
 
 Prepotency Mendel's law. 
 
 The art of breeding 
 
 Selection 
 
 Inbreeding 
 
 Page. 
 3 
 4 
 4 
 5 
 8 
 
 10 
 10 
 10 
 11 
 17 
 17 
 20 
 
 The art of breeding Continued. 
 
 Outcrossing 
 
 Pure breeding 
 
 The value of a pedigree 
 
 Livestock improvement 
 
 Grading up 
 
 Crossbreeding 
 
 Some incorrect ideas of heredity 
 
 Telegony 
 
 Maternal impressions 
 
 Conclusions... 
 
 Page. 
 
 24 
 24 
 26 
 31 
 31 
 32 
 33 
 33 
 35 
 36 
 
 BASIC FACTS ABOUT HEREDITY. 
 
 IN DEALING with the subject of heredity we must recognize 
 clearly the following facts: First, animal and plant forms, as a 
 rule, have developed gradually and very slowly, by very small 
 changes ; in short, by the process known as evolution. Second, what- 
 ever an animal has, so far as its inheritance is concerned, it gets from 
 its parents they get theirs from their parents, and so on clear back 
 to the beginning; nothing was imposed from the outside. For the 
 present, accept this fact without question. We shall try to make it 
 clear later. Third, a very clear distinction should be drawn between 
 the effects of inheritance and the effects of food and environment. 
 
 Every one who is at all familiar with domestic animals knows what 
 a wonderful effect the food an animal eats has on its development, 
 especially when it is young. It is also known that the younger an 
 animal is the more readily it is influenced by its food. Now, from the 
 very first moment that a young animal begins to develop, from the 
 very instant that growth begins with the fertilization of the egg 
 cell, it receives food from some source or it dies. When it is 
 only a single cell it is being fed. If a young animal after birth is 
 
 NOTE. In the preparation of this article, the writer received material assistance 
 from officers of the Bureau of Animal Industry, especially Messrs. F. R. Marshall (now 
 secretary of the National Wool Growers' Association), Sewall Wright, 'Dr. John E. 
 Mohler, and Mr. D. S. Burch. He is also greatly indebted to Mr. Dewitt C. Wing, of 
 Chicago, who made many helpful suggestions. 
 
 435054 
 
 3 
 
4 ::*. Farmers' Bulletin 1167. 
 
 easily influenced; by its food, how much more will the delicate little 
 creature, known as- the fetus'or' Embryo, be influenced by the character 
 of its food supply. A clear recognition of this fact will explain many 
 occurrences which are often attributed to supernatural influences, 
 and, at the same time, the breeder who recognizes this fact will not 
 neglect proper attention to the nourishment and care of the pregnant 
 mother as well as the nursing animal. 
 
 Accidents and disease also are important in their effects on the 
 growing embryo. If an incubator is neglected on a cold night and 
 the eggs become chilled, the hatch is seriously impaired and a large 
 number of chicks are killed in the shell. If an in-foal mare is sub- 
 jected to very heavy strains or forced to pull extremely heavy loads, 
 the foal may be born too soon or even be killed in the womb. Con- 
 tagious abortion may get into the herd without the owner's knowing 
 it and cause the loss of a large proportion of calves. Heredity, how- 
 ever, has nothing whatever to do with any of these things. 
 
 THE SCIENCE OF BREEDING. 
 
 THE UNIT OF LIFE. 
 
 The smallest unit of life is the cell. A single cell is very small, 
 usually of microscopic size. It is surrounded by a membrane, and 
 each cell usually contains a nucleus a sort of center of the things 
 that go on in the cell. The animal body contains millions of cells, 
 but those in which we are most interested at this moment are the 
 cells from the union of which a new animal life begins. They are 
 the germ cells. They contain the hereditary material which de- 
 termines the identity of each individual and which is known as the 
 germ plasm. This is the bit of life which passes down the line of 
 descent with each succeeding generation. It appears in the mother 
 in the egg cell, and in the father in the sperm cells. This material 
 is composed of elements which seem to be handed on unchanged 
 from generation to generation. Only a portion of the elements in 
 the germ plasm of the parent goes into each egg or sperm, however, 
 as is explained in more detail later. The element of chance enters to 
 such an extent in determining which elements shall go into a par- 
 ticular germ cell that there may be a marked dissimilarity among 
 individuals which are members of the same family. Even more im- 
 portant than the influence of food on the developing embryo and the 
 young, growing animal is the operation of chance in determining 
 the identity of the new life. 
 
 The cells from which all life starts are developed in the genera- 
 tive organs. The egg (the female cell) is developed in the ovary 
 of the female; the sperm (the male cell) is developed in the testicle 
 of the male. In mammals each female has two ovaries, one on 
 
Essentials of Animal Breeding. 5 
 
 each side, situated in the abdominal cavity. Connecting the ovaries 
 with the uterus are the Fallopian tubes. The uterus is the womb, 
 the chamber in which the young fetus develops until it is ready for 
 birth. The uterus connects with the vagina, through which the 
 sperm is introduced into the uterus and down which the young ani- 
 mal passes at birth. The genital organs and the urinary organs 
 have the same outlets from the body. 
 
 When an egg matures in the ovary it passes down the Fallopian 
 tubes into the uterus. If no sperm is introduced, the egg is thrown 
 off infertile. In female animals an egg matures at fairly regular 
 intervals, and this corresponds with some exactness to what is known 
 as the period of heat or oestrum. 
 
 The period of heat varies considerably in different species and 
 in different breeds and individuals of the same species. It usually 
 occurs at intervals of about three weeks. In mares it appears on 
 the ninth day after foaling, lasting two or three days. In cows it 
 appears in from three to four weeks after calving when the cow is 
 not suckling a calf, and in from six to eight weeks if she is. The 
 heat period lasts only about one day in cows. Sows come in heat 
 three days after farrowing, and not again until a week after the 
 pigs are weaned. In sheep, except for a few breeds, such as the 
 Dorset, ewes in North America ordinarily come in heat only in the 
 fall for a number of periods of two or three days each at intervals 
 of from two to three weeks. 
 
 Females usually accept service only during the period of heat. It 
 seems to make little difference when service is made, whether early or 
 late in heat. As a rule, not more than one service is necessary dur- 
 ing one period of heat to insure conception. After conception takes 
 place, the female does not generally come in heat again during preg- 
 nancy. 
 
 Male cells, or spermatozoa, are carried in the seminal fluid. There 
 is only one egg, as a rule, except in such animals as hogs, rats, and 
 others, which usually have several young at a birth. There are, how- 
 ever, millions of sperm cells, but only one of them is needed or used to 
 fertilize one egg. Let us now proceed to a consideration of the first 
 step in the formation of the new life. 
 
 THE BEGINNINGS OF LIFE. 
 
 The life which results when two animals are mated has its con- 
 trolling elements in the nuclei of the germ cells. These nuclei con- 
 tain a substance called chromatin, represented by very minute bodies 
 called chromosomes. Chromatin and chromosomes are found in all 
 cells all over the body, and the number of chromosomes in each cell 
 is the same for each species of animal. Except for the accessory 
 
6 Farmers' Bulletin 1167. 
 
 chromosome (which determines sex), they are always in pairs. 1 In 
 many of the domestic animals and in man the number of chromo- 
 somes is between 40 and 48, depending on the species. Just why this 
 number should be limited and invariable we do not know. It is no 
 more remarkable, however, that each cell in the hog's body, for ex- 
 ample, should have 40 chromosomes (which is the case) than that each 
 normal hog should have four legs. 
 
 This is easily understood until we come to explain what happens 
 when the egg cell is fertilized at conception. Obviously an egg 
 with 40 chromosomes and a sperm cell with 40 chromosomes could 
 not unite, because that would result in a cell with 80 chromosomes and 
 only 40 is the rule. It just wouldn't work, any more than a pig 
 with eight legs would work. Therefore, to prevent the doubling of 
 the number of chromosomes at conception, nature puts the germ 
 cells, both male and female, through a maturing process known as 
 maturation, so that, just before the two unite, each has only half 
 the normal number of chromosomes for the species, one from each 
 of the pairs present before maturation. 2 When the two cells unite, 
 therefore, the fertilized egg has the usual number of chromosomes' 
 carried by the cells of the species. This process occurs only in the 
 case of reproductive cells. 
 
 When two animals are mated, what happens? The reproductive 
 cells have gone through the maturing process and are now ready 
 for union. The sperm cells are active and move around until they 
 come into contact with the egg. Several may surround the egg, but 
 only one unites with it. The membrane surrounding the egg cell is 
 pierced by the head of a sperm cell. The two become one and the 
 egg is now fertile. It needs only nourishment to become in time a 
 full-fledged baby member of its race. 
 
 Food, of course, will have a profound influence on this little 
 mite of life, but, so far as we know, the character of the resulting 
 animal, its sex, its identity, and its individuality, whether it is to 
 be white or black, long-haired or short-haired, ring-streaked or 
 spotted, are now settled by the laws of life. This minute cell now car- 
 ries in itself all the force of inheritance from all the ancestors behind 
 it to the beginning of life on earth. Every champion you or I have 
 known began his career in just this way. Many, many influences 
 stepped in and had an effect on his subsequent development. Some of 
 these are easy to determine, but others are so obscure that theories 
 and fancies have grown up to explain them. 
 
 What value has this information for the practical breeder? Can 
 he use it in making his methods more efficient? He can not use it 
 
 1 For a discussion of the accessory or X-Chromosome, the reader is referred to textbooks. 
 
 2 Biologists call this process spermato genesis in the case of the male germ cells and 
 oogenesis in the case of the female germ cells. 
 
Essentials of Animal Breeding. 7 
 
 directly, but indirectly it can be most valuable to him, because it 
 explains many things that otherwise are difficult to understand. 
 
 Suppose we are breeding animals in which the number of chromo- 
 somes is only four (two pairs). By the time both egg and sperm 
 cells had gone through the maturing process, and the egg had been 
 fertilized, 16 different combinations would be possible, some of them 
 
 / 
 
 A 
 
 f 
 
 ' 
 
 What Chromosomes Look Like. 
 (Courtesy of Dr. E. E. Carothers.) 
 
 FIG. 1. A remarkable photograph of a group of maturing male germ cells taken 
 through a high-power microscope. The pairs of darkly stained chromosomes may 
 easily be seen in two of the cells in the act of separating to form the nuclei of two 
 new cells. Each of these resulting cells will have only half the original number of 
 chromosomes and will thus be ready for union with a similarly reduced egg cell. 
 Hereditary characteristics are transmitted in the chromosomes. 
 
 The factors which make up the identity of the chromosomes bear very much the 
 same relation to heredity that atoms bear to chemistry. 
 
 no doubt differing very little from each other, but others having 
 little mutual resemblance. In animals such as hogs, however, with 
 20 pairs of chromosomes in each cell, the possible combinations are 
 almost infinite in number. 3 
 
 These combinations are the results of chance. Here we have an 
 egg with 20 pairs of chromosomes, about to mature. Twenty of 
 these chromosomes only will be left when the egg is ready to unite 
 
 8 The number of possible combinations in this particular case is 1,099,511,627,776. 
 
8 Farmers' Bulletin 1167. 
 
 with the sperm cell. What 20 will it be? Chance alone can tell, 
 except that there will be one from each pair. Here comes the sperm 
 cell, to mature which a similar process was gone through. Chance 
 again determined that 20 out of the original 40 "chromosomes should 
 disappear and no determination can be made to show which 20 
 would prevail. But this is not all. The sperm cell does not come 
 alone. It .comes in swarms, but only one sperm cell penetrates the 
 cell membrane and fertilizes the egg. What determines which of 
 the thousands of sperm cells will be the one? Chance again. 
 
 The chromatin is the chief, if not the sole, determining factor in 
 the development of the identity of the new individual, and the 
 chromosomes are the agents by which this identifying process is 
 carried out. When we think of the great number of combinations 
 of chromosomes possible before fertilization is actually effected, we 
 begin to understand why it is that members of the same family 
 often do not look alike and why we have so many disappointments 
 in breeding animals. 
 
 If chance is the sole factor in determining what chromosomes shall 
 persist, where does intelligent breeding come in? Of what advan- 
 tage is it to exercise care in matings? Why not leave it all to 
 chance ? 
 
 The simple answer to these questions is that we can lessen the 
 probability of undesirable working of the laws of chance by increas- 
 ing the uniformity of the chromosomes. That is done by careful 
 selection to a certain type and by working with a group of animals 
 whose ancestry is known. The highest examples of such methods 
 are found in the work of breeders of purebred livestock where un- 
 broken and known lines of descent run back for a great many genera- 
 tions, sometimes for 50 years or more on a single farm under the 
 ownership of a single human family. The discussion of the subject 
 of selection will be found under that heading later. 
 
 THE GESTATION PERIOD. 
 
 From the time the egg is fertilized, developments are rapid. The 
 fertilized egg divides and subdivides with multitudes of subdivisions, 
 until in time the embryo " begins to look like something," and we 
 can make out the form of the animal and its parts. The time be- 
 tween the fertilization of the egg and the birth of the young animal 
 is known as the period of gestation. This period varies with the 
 kind of animal. The period for the common domestic animals is 
 shown below, followed by a table to determine how long a time may 
 be expected to elapse between service and birth. To make a practical 
 application of the table count forward the correct number of days 
 from the date of service. 
 
Essentials of Animal Breeding. 
 
 9 
 
 Gestation period of various animals. 
 
 Mare 11 months (340 days). 
 
 Jennet 12 months (365 days). 
 
 Cow 9i months (280 days). 
 
 Ewe 5 months (150 days). 
 
 Goat 5 months (150 days). 
 
 Sow 4 months (114 days). 
 
 Probable date of birth of young, female bred on first day of the month (Sewall 
 
 Wright). 
 
 
 Probable date of birth. 
 
 Date of 
 
 
 service. 
 
 
 
 
 
 
 Sow. 
 
 Ewe. 
 
 Cow. 
 
 Mare. 
 
 Jan. 1 
 Feb. 1 
 
 Apr. 25 
 May 26 
 
 May 31 
 July 1 
 
 Oct. 7 
 Nov. 8 
 
 Dec. 7 
 Jan. 7 
 
 Mar. 1 
 
 June 23 
 
 July 29 
 
 Dec. 6 
 
 Feb. 4 
 
 Apr. 1 
 
 July 24 
 
 Aug. 29 
 
 Jan. 6 
 
 Mar. 7 
 
 May 1 
 
 Aug. 23 
 
 Sept. 28 
 
 Feb. 5 
 
 Apr. 6 
 
 June 1 
 
 Sept. 23 
 
 Oct. 29 
 
 Mar. 8 
 
 May 7 
 
 July 1 
 
 Oct. 23 
 
 Nov. 28 
 
 Apr. 7 
 
 June 6 
 
 Aug. 1 
 
 Nov. 23 
 
 Dec. 29 
 
 May 8 
 
 July 7 
 
 Sept. 1 
 
 Dec. 24 
 
 Jan. 29 
 
 June 8 
 
 Aug. 7 
 
 Oct. 1 
 
 Jan. 23 
 
 Feb. 28 
 
 July 8 
 
 Sept. 6 
 
 Nov. 1 
 
 Feb. 23 
 
 Mar. 31 
 
 Aug. 8 
 
 Oct. 7 
 
 Dec. 1 
 
 Mar. 25 
 
 Apr. 30 
 
 Sept. 7 
 
 Nov. 6 
 
 Variations in the period of gestation for animals of the same kind 
 are not readily explained. Some animals, such as sows, are quite 
 uniform in the length of the gestation period. In mares there is a 
 considerable variation. It has been suggested that in mares some 
 time may elapse between the moment of service and the actual fer- 
 tilization of the egg by the sperm cell. In guinea pigs the size of 
 the litter affects the period of gestation, the period being shorter for 
 a large litter than for a small one. The health of the mother during 
 pregnancy also has an effect. 
 
 During the gestation period the young animal is carried in the 
 mother's womb and is not connected directly with her body. The 
 blood vessels and nerves of the mother do not connect with those of 
 the growing embryo, but from the start the little one has its own 
 little system of circulation and its own nervous system. It is carried 
 in an enveloping sac which is attached to the wall of the mother's 
 womb by buttons (cotyledons) which become detached when the time 
 comes. The, young are nourished by blood passing from the mother's 
 body through the walls of the uterus into the sac in which the fetus 
 is carried, and thence into the body of the young animal by trans- 
 fusion, much as water would pass into a paper sack if you should 
 lower it into a bucket of water. 
 3985 20 2 
 
10 Farmers' Bulletin H67. 
 
 INCUBATION PERIOD IN BIRDS. 
 
 In birds the incubation period corresponds to the gestation period 
 in mammals. The period which elapses from the time eggs are put 
 on to hatch until the chicks emerge is shown below. Young birds are 
 nourished in the embryonic stages of their development by absorbing 
 from the yolk the nutriment needed. 
 
 Incubation period of various birds. 
 
 Days. 
 
 Goose 30 
 
 Duck 28 
 
 Turkey 28 
 
 Guinea fowl 25 
 
 Chicken 21 
 
 Pigeon 17 
 
 Much may be learned by any one of a studious nature by careful 
 observations of the deA r elopment of the embryo of chickens. The 
 germinal disk may be plainly seen even in a fresh-laid egg, which, 
 whether fertile or not, looks the same to the naked eye. When put 
 into an incubator, however, the fertile egg begins to develop rapidly, 
 and the transformation in the brief period of three weeks is won- 
 derful. The course of this development in fertile eggs can be dis- 
 tinguished easily from day to day by the familiar process of candling 
 eggs, or it can be studied in detail by carefully breaking the eggs 
 into a saucer. 
 
 DETERMINATION OF SEX. 
 
 As the growth of the embryo progresses, sex becomes apparent. 
 Sex seems to be determined by one of the chromosomes, and is prob- 
 ably settled at the time of conception. 4 The determination of sex 
 is therefore a matter of chance over which the breeder probably has 
 no control. For practical purposes, the breeder will find that, over 
 a period of years, he gets nearly equal numbers of both sexes. 
 
 FECUNDITY. 
 
 The subject of fecundity is of great practical importance to 
 breeders of animals. Fecundity ^depends very largely on the number 
 of eggs which are matured at a given time by the female. Animals 
 in which multiple births are the rule (of which sows are a common 
 example) not only mature a considerable number of egg cells at 
 one period of heat, but each one. is fertilized by a separate sperm 
 cell. In some cases, how r ever, the fertilized egg may divide and 
 twins or a larger number of young result. Such twins are known 
 as identical twins, and are usually of the same sex, with very strong 
 
 *See note (2) page 6. 
 
Essentials of Animal Breeding. H 
 
 points of similarity. Young from multiple births, resulting from 
 the fertilization of different egg cells, show as wide a difference 
 in individual characteristics as young resulting from separate births. 
 The most prolific of the common domestic animals are the birds. 
 The domestic hen may lay more than 200 eggs in a single year. 
 
 The common practice of British shepherds, known as "flushing" 
 ewes, has been claimed to increase the proportion of lambs in the 
 flock. This practice consists in giving the ewes an increase in their 
 feed, both grain and succulent pasture, so that they are gaining in 
 weight and condition at breeding time. No exact scientific data 
 have been available until recently, when Marshall and Potts, of the 
 Bureau of Animal Industry, conducted experiments which confirmed 
 the correctness of the British practice. They also have evidence 
 which indicates that the success of the practice depends on cutting 
 off the grain ration and putting the ewes on short pasture as soon 
 as thev are bred. 
 
 
 - . r , -:;-:./- 
 
 L. 
 
 What a Good Mother Can Do. 
 
 FIG. 2. The ewe at the right was lambed in March, 1914. She was a prize winner as a 
 yearling and as a two-year-old. Her first lamb was a ram dropped in 1916. Since 
 then she has had seven lambs. The other two ewes are her twins of 1919 and were 
 shown in the trio for Hampshire ewe lambs, winning first prize at the 1919 Inter- 
 national Live Stock Exposition. The lamb at her side is her 1920 contribution to 
 the wealth of America's purebred livestock industry. 
 
 The rules or laws of the inheritance of fecundity are not all known, 
 but to some extent it is dependent on inheritance from the mother; 
 therefore, the selection of females which have a tendency to produce 
 a large number of young at a birth will tend to increase the returns 
 from the flock or herd. This is of practical importance in the case 
 of hogs, sheep, goats, and poultry. Twins in cattle are objectionable 
 unless of the same sex. When a heifer is a twin with a bull calf, 
 the heifer is known as a " freemartin " and in the majority of in- 
 stances is sterile. 
 
 PREPOTENCY MENDEL'S LAW. 
 
 Prepotency is the power of an animal, male or female, to stamp its 
 characteristics on its offspring. If this ability is handed on to sons 
 
12 
 
 Farmers' Bulletin 1167. 
 
 and daughters, we say that the stock " breeds on." In rare instances 
 an animal, usually a male, is found, which has such power as a breeder 
 that it leaves an indelible impress, even to the extent of becoming the 
 fountain head of a new breed, such as the stallions Justin Morgan, 
 Hambletonian 10, and Denmark. 
 
 Most of the cases of prepotency which the breeder usually meets 
 with are probably instances of the operation of what is called 
 Mendel's law. A clear explanation of this great law of heredity can 
 not be made within the scope of this short article, and the interested 
 reader, if he cares to go into the subject in detail, is referred to Dr. 
 Wright's bulletin. 5 
 
 How Good Blood " Breeds on." 
 
 FIG. 3. Cannon, Standardbred stallion at head of United States Government stud, 
 Buffalo, Wyo., a horse which has been remarkably successful in stamping his 
 characteristics on his offspring. Photograph taken when Carmon was 20 years old. 
 
 It must be pointed out, however, that most operations of heredity 
 are not simple; on the contrary, they are highly complex and often 
 extremely difficult to understand. The chief use which the practical 
 breeder of domestic animals can make of Mendel's law at this time 
 is to find in it an explanation of occurrences that otherwise have no 
 rational explanation. 
 
 One of the most interesting applications of Mendel's law in cattle 
 breeding is the inheritance of the polled characteristic. If we breed 
 a horned cow to a Red Polled, Galloway, Angus, or other true polled 
 bull, the chances are 9 to 1 or better that we shall get a polled calf. 
 The white face of the Hereford appears to be a similar instance. 
 
 5 TJ. S. Department of Agriculture Bulletin 905, "Principles of Livestock Breeding." 
 
Essentials of Animal Breeding. 
 
 13 
 
 How Good Blood " Breeds on." 
 
 FIG. 4. Albion, one of Carmon's first sons used in the Government stud as a sire. 
 Note the remarkable resemblance between this horse and Carmon. Photograph was 
 taken when Albion was nine years old. 
 
 i 
 
 
 How Good Blood " Breeds on.' 
 
 FIG 5. Defender, son of Albion. Photograph taken when Defender was six years 
 old. Note that the type has been handed down from grandfather to grandson. 
 
14 
 
 Farmers' Bulletin 1167. 
 
 If we breed a common cow to a Hereford bull, we get a calf with a 
 white face. We say, therefore, that polled breeds are very prepotent 
 so far as " taking the horns off " is concerned, and that the Hereford 
 is prepotent in putting a white face on his calves. This may happen 
 either way ; that is, polled bull and horned cow, or horned bull and 
 polled cow, Hereford bull and plain-faced cow, or plain-faced bull 
 and Hereford cow. The temptation is to make great claims for the 
 prepotency of the breed as a whole on the evidence of one or two 
 points only. For see what happens when we mate a Hereford with 
 one of the polled breeds. Then we get a polled, white- faced calf. 
 
 How Bad Blood " Breeds on." 
 
 FIG. 6. A spotted stallion of nondescript breeding used extensively as a sire in the 
 community where he was owned. Note not only the bad color, which is almost 
 unmarketable, but also the curby hocks and generally mean appearance. 
 
 These points are not prepotency at all, but manifestations of Men- 
 delian " dominance." The polled character is dominant over the 
 recessive horned character, and the white face over the recessive plain 
 face; but these cases do not necessarily indicate that the animal is 
 particularly prepotent in other characters of much more practical 
 importance. The same rule seems to apply in the inheritance of the 
 black color in sheep, black acting apparently as a recessive to the 
 usual white color. It can readily be eliminated by culling out the 
 black lambs. 
 
 A great many data have been accumulated as to the characters 
 in animals which illustrate the operation of Mendel's law, but 
 
Essentials of Animal Breeding. 
 
 How Bad Blood " Breeds on." 
 
 FIG. 7. A daughter of the spotted stallion. Observe crooked hind legs, as well as 
 
 bad color. 
 
 How Bad Blood " Breeds on." 
 
 FIG 8. Another daughter of the same stallion. Note how the curby hocks have been 
 transmitted and how there is also a striking tendency for the spotted color to 
 prevail. Some of the stallion's bad qualities appear in the forelegs on this 
 individual. 
 
16 Farmers' Bulletin 1167. 
 
 apart from the horns of cattle, coat color, eye color, and the like, 
 the application of this law to livestock breeding has a long way 
 to go before its principles are adaptable to practical use by breeders. 
 It is fairly certain, however, that many of the obscure happenings 
 in animal breeding are really manifestations of Mendelism. Most 
 cases of atavism ("throw backs" to a remote ancestor), for ex- 
 ample, are probably Mendelism in practice. 
 
 The animal structure is so diverse and complicated that the de- 
 termination of the application of Mendel's law to the inheritance 
 of the characters which affect the commercial value of domestic 
 animals is a task of tremendous magnitude. Great progress has been 
 made in laying the foundations for the scientific study of animal 
 breeding by working out the principles of this law, and we may ex- 
 pect still greater progress in the future. Biologists who are studying 
 heredity have their faces set in the right direction. The accomplish- 
 
 FIG. 9. Purebred Hereford sire, scrub dam, and offspring. Note how the character- 
 istic markings of the Hereford sire, especially the white face, are transmitted. 
 
 ments of the last twenty years in the study of heredity have taken this 
 subject out of the field of guesswork, and for this service all animal 
 breeders are under obligations to Mendel and his disciples. 6 If, by 
 skillful selection and intelligent breeding methods we can get re- 
 sults of permanent value; if, with the present knowledge, we can 
 make real progress in animal breeding, we can afford to wait for 
 the more definite working out of Mendel's law, with the assurance 
 that this law controls the mechanics of heredity in domestic animals 
 and that any practical application of it to animal breeding will add 
 to our store of useful knowledge and to the efficiency of our breeding 
 methods. 
 
 6 The discovery of this law by the Austrian monk, Gregor Mendel, in 1865, its virtual 
 disappearance for 35 years and its rediscovery simultaneously by several investigators 
 working independently, form one of the romances of science. Mendel's papers attracted 
 very little attention when published, owing, no doubt, to the intense interest of the 
 world in the researches of Darwin. Mendel died in 1884 without realizing the importance, 
 to humanity, of the work which he had done. 
 
Essentials of Animal Breeding. 17 
 
 THE ART OF BREEDING. 
 
 SELECTION. 
 
 Keeping in mind the principles laid down in the foregoing pages, 
 it is clear to every one that in order to make the best out of the 
 hereditary material represented in one's herd, and to use the laws 
 of nature to the best advantage, one must have clearly in mind a 
 standard which he sets for himself as the ideal toward which he 
 must work. This standard must be definite and should be as prac- 
 tical and simple as possible. The exercise of selection, wisely and 
 judiciously pursued, offers the breeder one of the two most effective 
 means of bending to his own purposes the operations of chance, 
 which otherwise nature will use to his confusion and undoing. 
 
 We have made the statement already that the hereditary material 
 is passed down from generation to generation without change ex- 
 cept so far as the operation of the laws of chance may have affected 
 the process, beginning with the maturation of the germ cells. It is 
 plain, however, that constant selection of a good type will increas- 
 ingly intensify the properties of a given set of characteristics (in 
 other words, of a definite type), but that this selection must be pur- 
 sued constantly because the chromosomes which tend to produce the 
 less desirable types continue to be present, although in decreasing 
 numbers. If the force which has been selecting the desirable 
 chromosomes is removed, then the undesirable ones may once more 
 prevail. In other words, our modern breeds of farm animals are an 
 improvement over the stock from which they sprang. There is, 
 therefore, a constant pull backward and downward against which 
 the breeder must work by wise selection and skillful matings. If 
 this intelligent direction by human skill should be removed, our 
 animal stock would rapidly degenerate to the level of the types of 
 centuries ago. 
 
 Selection should be -designed to correct faults in the parents, and, 
 as a rule, the male is depended on to do it. A few concrete cases will 
 illustrate. If the females have a tendency to be too leggy, select a 
 male that is compact and close to the ground. If the backs are not 
 ideal, select a male with an exceptionally strong back. If the sow's 
 feet are not the best, get a boar that is unusually strong in his feet 
 with strong, upright pasterns. We might multiply these illustra- 
 tions indefinitely. Therefore, a sire should be a better individual 
 than the females with which he is to be mated ; otherwise the stand- 
 ard of the herd or flock may decline. To some extent a breeder may 
 extend these principles to the grandparents, but for practical work 
 on a farm that is producing market stock it is commonly unnecessary 
 to go farther back than the sire to be selected. In other words, don't 
 3985 20 3 
 
18 Farmers' Bulletin 1167. 
 
 buy a poor male merely because some one tells you he has a good 
 pedigree. 
 
 The breeding animals selected should look the part. Good bone; 
 deep, broad chests; strong, broad backs; and fully developed bodies 
 should be emphasized. Especial attention should be paid to the head, 
 for that part of the body tells many a story which otherwise would 
 be overlooked. Width between the eyes, full, prominent eyes of 
 pleasing appearance, broad muzzles, and prominent nostrils indicate 
 
 Hereford Calf Illustrating Character. 
 
 FIG. 10. Compare this picture with those of other bulls, shown. Each one shows 
 strong masculinity. Each one has an individuality aa marked and striking as the 
 individuality shown in photographs of human beings. 
 
 points of value both to the breeder and the feeder. In males, strong 
 evidence of masculinity is important. The evidence of the masterful 
 impressiveness of the masculine sex is often apparent in very young 
 animals and may be taken to indicate a youngster that with proper 
 feed and care will grow out into an impressive sire. In females we 
 look for femininity, without indications, however, of weakness of 
 constitution. Avoid cows, for example, with heads like those of 
 steers. These points make up in total what breeders call " charac- 
 
Essentials of Animal Breeding. 19 
 
 ter " and are among the most important considerations which a 
 breeder must bear in mind in building up his herd or flock. 
 
 Good feed, care, and attention are valuable adjuncts to selection. 
 Unless feeding permits full development we can not select intelli- 
 gently the animals which have received and can transmit the charac- 
 ters we desire to perpetuate. Starved animals which never have had 
 an opportunity to demonstrate their capacity to produce meat, milk, 
 wool, or other valuable commercial products, furnish poor material 
 from which to select individuals capable of maximum and most 
 economical production. 
 
 One must use these rules of selection with judgment and common 
 sense. While faults undoubtedly can be corrected by the use of 
 
 Idolmere. 
 
 FIG. 11. Grand champion Aberdeen-Angus bull at the 1919 International Live Stock 
 Exposition. One of the greatest bulls of the breed ever seen in an American show 
 ring. An exceptional photograph of a great bull showing not only splendid beef 
 conformation but outstanding breed character also. Note especially the strong 
 character as shown in the head and neck, as well as the great length of the bull and 
 his remarkable smoothness. 
 
 males of superior individuality, it may be unwise to use some females 
 for breeding even market stock because they may be too inferior for 
 even this purpose. To sell them and substitute better individuals, 
 either high grades or purebreds, is often the more sensible course 
 and the more profitable in the end. 
 
 Selection alone, however, is not certain to result in steady progress. 
 Different combinations of hereditary elements may result in ap- 
 parently the same characteristic. In practicing selection a man may 
 introduce at any time the blood of a line which merely looks like 
 that of his 'own stock, but which breeds differently. The result is 
 the undoing of past progress, the next generation showing the vari- 
 
20 Farmers' Bulletin 1167. 
 
 ability characteristic of the second generation of a cross. Only by 
 breeding within relatively narrow limits can one be reasonably sure 
 that he is mating animals which both look alike and have the same 
 heredity. 
 
 INBREEDING. 
 
 Next in importance to selection as a means of improvement in 
 breeding animals, the most effective process at the command of the 
 breeder is the judicious mating of related animals. This process is 
 known as inbreeding, and various terms, such as line breeding, close 
 breeding, and incestuous breeding, have been used to define varying 
 degrees of intensity of the process. 
 
 Jersey bull, Pogis 99th of Hood Farm No. 94502. 
 
 FIG. 12. Animals such as this one show strong evidence of breed character, mascu- 
 linity, and impressiveness. 
 
 Inbreeding is one of the most discussed subjects in the whole 
 field of genetics. All sorts of bad results are attributed to it. Lack 
 of vigor, nonresistance to disease, decline in size and fecundity, and 
 even sterility are the fate of inbred animals, in the minds of many 
 people. These ideas have a certain basis in fact, and often extend to 
 farmers, who sometimes refuse to buy males which have inbred pedi- 
 grees. Breeds and families which have been intensely inbred for sev- 
 eral generations develop manifestations of constitutional weakness 
 which, it seems, can be explained only on the grounds of their close 
 relationship. Scientific data of exact and elaborate scope, worked 
 out under controlled conditions, are not abundant on this point. 
 
Essentials of Animal Breeding. 21 
 
 We have, on the other hand, the accepted fact that progress in 
 animal breeding began only when breeders began to inbreed. The 
 work of Bakewell, who experimented during the last half of the 
 eighteenth century, which made the greatest impression was the 
 methods he used, and the method that has been most far-reaching 
 in its results was that he mated his animals with first regard to their 
 individual suitability for the mating, and with secondary importance 
 placed on their relationship. Since the time of Blakewell every 
 breeder who has made an impress of permanent importance on his 
 breed has used inbreeding as his most useful working tool. 
 
 Purebred Ayrshire Bull, Hobsland Perfect Piece 16933. (Senior Grand Champion 
 Ary shire Bull. National Dairy Show, 1914.) 
 
 FIG. 13. A good breeding animal impresses the observer in many ways. The pose of 
 this bull, his lines, and the sweep from the head to the tip of the tail give an 
 unmistakable impression of individuality, power, and merit. 
 
 When we mate related animals we are bringing together animals 
 with a more nearly uniform character in their hereditary material 
 than when we mate those that are not related. We are, therefore, 
 increasing the probability that the offspring will be like the parents. 
 But there may be hidden in the hereditary material the factors of 
 an undesirable character. In other words, we may not know all 
 that we should know about the ancestors. Back somewhere, per- 
 haps, was a bad one whose traits are being bred out by selection in 
 each successive generation. If we mate two related animals carry- 
 ing this defect, we greatly increase the chance of perpetuating it. 
 Instead of having an even chance or better of keeping the defect under 
 
22 
 
 Farmers 9 Bulletin H67. 
 
 subjection by not inbreeding, we double the chance of its appearing 
 when we do inbreed. It seems possible to inbreed some animals 
 much more intensely than others, and certain strains of breeds in 
 the same species exhibit similar traits. To cite specific instances, 
 cattle which have a special susceptibility to tuberculosis, horses with 
 a tendency to certain unsoundness, such as roaring or spavin, should 
 not be inbred. The safe rule, therefore, is not to mate closely re- 
 lated animals which have the same defects, either themselves or in 
 their immediate ancestors. 
 
 Percheron Stallion, Dragon. 
 
 FIG. 14. Descendant of a long line of impressive ancestors and himself a sire of 
 
 valuable draft horses. 
 
 Inbreeding should be practiced only by the most skillful breeders, 
 and by them only when they have definite knowledge of the an- 
 cestry. Judiciously used, inbreeding results in a rapid fixing of 
 type and enables the breeder to obtain results much more rapidly 
 than without its use. It is like any other high-powered implement. 
 Properly used, it is a wonderful adjunct to human efforts; in the 
 hands of the ignorant and careless it is a source of danger. 
 
Essentials of Animal Breeding. 
 
 23 
 
 The purchaser of inbred males, however, need have no fear of using 
 them if they are creditable representatives of the breed. As a matter 
 of fact, he should prefer inbred males to others, especially if they are 
 not related to his females, because they are more nearly alike in their 
 hereditary material, and for that reason more likely to reproduce 
 themselves with uniformity. They are usually sold under a guaran- 
 ty that they are breeders (or they should be so sold), and if they do 
 not breed, any reputable breeder will replace them. It is a general 
 rule that inbred animals, when mated to unrelated ones, even though 
 
 Clydesdale Stallion, Fyvie Baron. 
 
 FIG. 15. Note intelligent head and strong, crested neck, as well as evidence of vigor- 
 ous constitution, indicated by depth of body. 
 
 the latter themselves are inbred, produce offspring larger and more 
 vigorous than either parent. From every standpoint, therefore, an 
 inbred sire should be desirable to use in a farmer's herd, provided the 
 animal is a good individual. The farmer should make certain of 
 this fact. Then he should ascertain that the strain itself is vigorous, 
 and finally he should have a guaranty that the animal bought will 
 prove to be a breeder. If these conditions are met, the farmer will 
 find inbred males much more impressive and will have a much more 
 rapid return in improving his stock than if he had used males which 
 were not inbred. 
 
24 Farmers' Bulletin 1167. 
 
 Whether a breeder should or should not inbreed his stock is a 
 matter which he must settle for himself. The successful use of in- 
 breeding is one of the best tests of a breeder's skill, and no man should 
 inbreed unless he is confident that he possesses the requisite skill to 
 make such a step successful. Generally speaking, the inbreeding of 
 market stock is unwise; but the use of inbred males on the females 
 of such a stock may be of the highest value, provided the breeding 
 establishment which produced the males has not been injured by 
 inbreeding. Such a fact can be readily ascertained. 
 
 Inbreeding fixes characters which can be fixed, but one of its most 
 valuable consequences is bringing clearly to light the relative merits 
 of different strains in such characters as fecundity, resistance to 
 disease, and the like, which are affected so much by factors other than 
 heredity that they can not be fixed in individuals. In these cases 
 progress is more likely to result from selection of strains than from 
 the selection of individuals. 
 
 A real danger from inbreeding is not to be urged against the 
 practice itself, but against the peculiar infatuation which breeders 
 acquire for certain bloodlines. Once let a given line of breeding 
 demonstrate its excellence for the production of a certain valuable 
 type, and every progressive breeder strives to acquire some of this 
 valuable blood. The strain soon becomes " fashionable." From 
 this stage to breeding for the pedigree rather than for the animal 
 is an easy step which is taken much too often. The corrective for 
 such methods is the show ring, with competent and fearless judges 
 in authority. 
 
 OUTCROSSING. 
 
 Quite the converse of inbreeding is the practice of outbreeding or 
 outcrossing. Even in plants which are usually self-fertilized, nature 
 has provided for an occasional outcross that materially increases the 
 vigor, stamina, and general well-being of the stock. In animals 
 which have been intensely inbred, outcrossing has interesting and 
 important results. Mating to stock which has not been inbred 
 results in increases in size and vigor. A similar result also follows 
 the mating of two strains, both of which have been inbred, but which 
 are not closely related to each other. 
 
 PURE BREEDING. 
 
 Step by step we climb the ladder of the art of breeding until we 
 finally reach the top in the breeding of purebreds, the most fascinat- 
 ing, the most inspiring, and the most remunerative branch of animal 
 breeding when successfully followed ; the most difficult and the most 
 disappointing when not successful. The successful breeder of this 
 class of animal is far more than a business man or a farmer. He is 
 an artist, and the artistic appeal is first in importance to him. 
 
Essentials of Animal Breeding. 25 
 
 The basis of pure breeding in the United States, except in the case 
 of poultry and pet stock, is pedigree registration. Animals must be 
 not only purebred, but they must be registered in the book of record 
 established for the breed. 
 
 Standards in pure breeding are more exacting and more compli- 
 cated than in breeding solely for the production of meat, wool, milk, 
 or eggs, but they should be practical, because the proof of the prac- 
 tical value of a breeder's work is the demand which is sustained in 
 the long run for his breeding animals. The surplus of the registered 
 purebred establishments goes to improve the native and unregistered 
 grade herds and into purebred herds of less merit. A high stand- 
 ard is therefore absolutely essential to maintain quality, average 
 excellence, and the reputation of the herd. Practical ideals must have 
 quite as much weight as purely commercial considerations in the 
 determination of the standards. 
 
 A breeder's success depends to a very large extent on his ability 
 as a qualified judge of animals, on his knowledge of the pedigrees 
 of his animals, and on his acquaintance with the characteristics of 
 the ancestors of those animals. The breeder's ability as a judge 
 must be based on an instinctive gift to recognize animal types and 
 carry them clearly in mind. This is of even more importance than 
 a knowledge of pedigrees, because a knowledge of pedigrees is of 
 practical value only as it gives its possessor an acquaintance with 
 the individuality and type of the ancestors in the pedigrees, which 
 he may use in making effective matings and thus perfecting the 
 type of his animals. One of our most eminent breeders of hogs 
 once made the statement, "I breed my hogs in the barnyard, with 
 the animals before me, not in my parlor with their pedigrees before 
 me." That homely statement carries a truth which every ambi- 
 tious young breeder should follow. Before deciding to make a 
 certain mating, the man who made this statement is said to spend 
 hours studying his breeding animals, going over their character- 
 istics, and especially recalling to mind the characteristics of their 
 parents, grandparents, and more remote ancestors. If this review 
 is satisfactory, the mating is made ; if not, some other is tried. 
 
 To sum up, knowledge of a pedigree must not stop with the 
 routine knowledge of the names of the animals which compose it. 
 The breeder must know also the characteristics of these animals, as 
 far back as possible, their weaknesses as well as their strong points. 
 When he possesses this information the breeder can more intelli- 
 gently mate individuals and blend bloodlines. He has then a prac- 
 tical working knowledge of pedigrees. The study of pedigrees, 
 therefore, based on a knowledge of the characteristics of the ani- 
 mals composing them, is indispensable to the man who would excel 
 as a constructive breeder. 
 
26 
 
 Farmers' Bulletin 1167. 
 
 THE VALUE OF A PEDIGREE. 
 
 No one breeds animals without dealing with pedigrees. The 
 common phrase " pedigree stock," as a synonym of " well-bred " or 
 " purebred " in describing livestock, is a misnomer. All plants, 
 all animals, all people have pedigrees, but all information about 
 these pedigrees is not available. Pedigrees become known because 
 of merit in some individual which stands out above his fellows. 
 
 The Sire of a Grand Champion. 
 
 FIG. 16. To achieve the highest results in livestock production pure blood is most 
 likely to result satisfactorily. Illustration shows the Shorthorn bull, Lavender 
 Sultan, sire of the three steers shown in figure 18. This bull is a remarkably 
 impressive sire with wonderful thickness of flesh. Note how his thick flesh is 
 transmitted to his sons. Compare this picture with figures 17 and 18. 
 
 His progeny are watched, and if they have merit above the average 
 they are "saved for breeding purposes," and by and by we have 
 a line of known descent and ultimately perhaps a pedigree of dis- 
 tinction and formidable appearance. They are written into genealo- 
 gies, herdbooks, flock books, and studbooks, and the inheritance of 
 decades and even of centuries becomes in time a matter of written 
 record. 
 
 The proof of the value of the pedigree itself is the worth of the 
 animals it produces. The value of animals with certain pedigrees 
 
Essentials of Animal Breeding. 
 
 27 
 
 depends upon their ability to produce desirable types with greater 
 excellence and uniformity than animals with other pedigrees or 
 
 The Dam of a Grand Champion. 
 
 FIG. 17. Merry Sempstress, dam of Merry Monarch, the grand champion steer at the 
 International Live Stock Exposition in 1919. Note not only her beef conformation 
 but her good feeding qualities, clearly indicated in a head which is almost an ideal 
 feeder's type, as well as an ideal breed type. She shows excellent indications of 
 real feminine character. 
 
 A Triumph of Breeding and Feeding. 
 
 FIG. 18. Merry Monarch (right), grand champion steer at the 1918 International Live 
 Stock Exposition, and two other prize-winning sons of Lavender Sultan. Compare 
 with figures 16 and 17. 
 
 with no known pedigrees whatever. The power of the animal with a 
 known pedigree to reproduce its type has been intensified by selection. 
 Therefore, if the matings which have been made in constructing the 
 
28 
 
 Farmers 1 Bulletin 1167. 
 
 pedigree have not been directed by a high order of skillful selection, 
 the animal may have intensified powers of producing an undesirable 
 type, and may be what is commonly designated a " scrub purebred.'' 
 The purchase of an animal or its use for breeding purposes solely 
 on account of its pedigree is a dangerous matter and may result in 
 much more harm than good. 
 
 What is the most important part of the pedigree? Usually only 
 the ancestors which are " close up " are those which are of practical 
 importance in determining the identity of the individual. Assuming 
 that Mendel's law governs animal inheritance, we may occasionally 
 
 The Main Points of a Pedigree. 
 
 FIG. 19. A graphic representation of the relative importance of ancestors in the first 
 four generations. Families in livestock often trace their foundation to a single animal 
 which may not be reached within ten generations. It is quite as important to know 
 what sort of animals make up the later matings as it is to know to what family the 
 animal belongs. The proof of the value of a pedigree is the worth of the animals it 
 produces. 
 
 expect to find an off-type occurring, but by the repeated culling out 
 of such types the frequency of their occurrence is being constantly 
 reduced. Therefore, if we are sure of the parents and know what is 
 in the first three or four generations of an animal's pedigree, we 
 know the most important facts about that pedigree. In generations 
 beyond the third or fourth the influence of any ancestor is so slight 
 that for practical purposes it may be ignored. 
 
 In a four-generation pedigree there are 30 ancestors, all of which 
 may be different individuals. Usually in pedigrees of most purebred 
 herds there are fewer than 30 separate individuals, depending on the 
 amount of inbreeding in the pedigree. The chart (fig. 19) shows this 
 
Essentials of Animal Breeding.. 
 
 29 
 
 fact graphically. Suppose there is no inbreeding in a four-genera- 
 tion pedigree, the chance that one of the animals in the fourth gen- 
 eration will dominate the pedigree above all others is very small 
 indeed., The chart thus shows graphically the relative importance 
 
 Grading Up With Sheep. 
 
 FIG. 20. The ewe at the left is a Mississippi Piney-Woods native. The lamb is her 
 produce by a purebred Shropshire buck. At four months of age the lamb outweighed 
 not only her mother but any other ewe in the flock. Note the absence of wool on 
 the belly of the ewe and the good, thick, uniform fleece of the lamb. 
 
 of the respective ancestors for four generations. Each figure in the 
 chart is just half the size of the one in the generation preceding, and 
 this conforms fairly well to the standard formula of inheritance. 
 
Farmers' Bulletin 1167. 
 
 The chance of grandparents' dominating the inheritance of the 
 mating can not be more, and is undoubtedly much less, than 1 in 
 
 Grading Up With Dairy Cattle. 
 
 FIG. 21. The result cf 15 years' consistent work with purebred bulls, 
 grade Jersey herd bred up from a native foundation. 
 
 A Mississippi 
 
 6; the chance of a great-grandparent is less than 1 in 14; and the 
 chance of a great-great-grandparent (fourth generation) is less 
 
 than 1 in 30, provided no in- 
 breeding occurs. In a pedigree 
 covering 10 generations (which 
 can easily be run out with almost 
 any of our well-established breeds 
 of domestic animals) there are 
 2,046 ancestors, more than half 
 of which are in the tenth genera- 
 
 k; J^ : tion. Yet cattle are sometimes 
 
 "^ilBto **' s ld at a premium because a 
 
 certain cow appears in the 
 pedigree as far back as the tenth 
 generation or even further, re- 
 gardless of the merit of animals 
 much further down in the pedi- 
 gree. Or a pedigree may be 
 classed as unfashionable and the 
 animal carrying it may be dis- 
 criminated against, regardless of 
 
 Plymouth Rock males. it s individual excellence, because 
 
 some unpopular animal may have appeared in an extremely remote 
 generation. 
 
 Value of Pure Blood. 
 
 FIG. 22. In 1915 the Bureau of Animal 
 Industry purchased on the Washington 
 (D. C.) market a flock of mongrel hens. 
 These hens were mated to standardbred 
 males to show how mongrel flocks could 
 be improved by grading up. This illus- 
 tration shows a mongrel hen, and the 
 
Essentials of Animal Breeding. 
 
 31 
 
 LIVESTOCK IMPROVEMENT. 
 
 GRADING UP. 
 
 The process of improving native stock by breeding the females to 
 purebred males is termed grading up. The first cross is usually a 
 
 Value of Pure Blood. 
 
 FIG. 23. Barred Plymouth Rock male used 
 for the first cross on mongrel hens such 
 as the one shown in the preceding 
 illustration. 
 
 Value of Pure Blood. 
 
 FIG. 24. First-cross pullet of mongrel hen 
 shown in figure 22 and sired by male 
 shown in figure 23. 
 
 Value of Pure Blood. 
 
 FIG. 25. Second-cross pullet. Size, con- 
 formation, and color of pattern have 
 been greatly improved. 
 
 Value of Pure Blood. 
 
 FIG. 26. Third-cross pullet. Fanciers 
 who did not know how she was bred 
 would call this pullet a good representa- 
 tion of the breed. 
 
 very noticeable improvement over the native stock. When the 
 females of this mating are bred to a male of the same breed, greater 
 
32 
 
 Farmers' Bulletin 1167. 
 
 fixity of type appears. Continued use of males of the same breed 
 results, in a comparatively short time, in animals which are practi- 
 cally purebred, although not eligible to registration and therefore not 
 salable as purebreds. 
 
 In grading up, consistent methods should be used and males of the 
 same breed used, cross after cross; otherwise the stock will be mon- 
 grelized instead of improved. Males should also be better indi- 
 viduals in all respects than the females with which they are mated, 
 in order that each successive cross may be an improvement over the 
 ones which went before it. 
 
 Uniformity Quickly Obtained by Use of Purebred Males. 
 
 FIG. 27. Kids at the Experiment Farm of the Bureau of Animal Industry, Beltsville, 
 Md., by purebred Saanen bucks on foundation of native does. 
 
 CROSSBREEDING. 
 
 Crossbreeding is the mating of purebred animals of different breeds 
 of the same species. Crossbred animals are usually larger and more 
 vigorous than either parent. Their hereditary material, however, 
 is so complex that there is no certainty as to what results will come 
 from mating them. Except to produce market animals, crossbreed- 
 ing should be used only by the highly skilled breeder, and it is not 
 practicable in his case unless he has an opportunity to place the 
 progeny on the market for breeding purposes. American practice in 
 livestock breeding does not encourage the development of new breeds 
 except in the case of poultry and pet stock. Therefore the practical 
 man, as a rule, will leave this matter to the experimentalists. 
 
Essentials of Animal Breeding. 33 
 
 SOME INCORRECT IDEAS OF HEREDITY. 
 
 From the earliest beginnings of rational mental processes human 
 beings have asked the question " Why ? " Failing to receive an 
 answer concerning things which they could not understand they 
 have theorized and developed explanations as a result of such theories 
 which often have not had any basis in fact. From the time when the 
 simple shepherds of Asia watched their flocks beneath the stars and 
 wondered at the mysteries of nature around, above, and beneath 
 
 A Fast-Disappearing Type. 
 
 FIG. 28. Native Piney-Woods sow. Note the wattles. These sows are prolific, good 
 milkers, and good mothers. In other respects they have nothing to commend them. 
 Purebred sows are just as prolific, just as good milkers and mothers, and make pork 
 far more rapidly and more economically. 
 
 them, man has marveled at the mysteries of heredity. In some form 
 or other many of these meditations have persisted until modern 
 times as beliefs for which no unassailable proof has ever been pre- 
 sented. 
 
 TELEGONY. 
 
 These beliefs are sometimes intensified by an apparent confirmation 
 from scientific sources. Possibly the most outstanding instance of 
 this kind is the famous case of Lord Morton's mare, which in the 
 opinion of the great Charles Darwin confirmed the theory of telegony. 
 
34 Farmers' Bulletin 1167. 
 
 This theory was that the first male to impregnate a female perma- 
 nently endowed the female with his characters, so that subsequently 
 she would always exhibit them in her progeny. If this male was of 
 another breed the female became a crossbred by means of this first 
 impregnation. The Lord Morton mare was a Thoroughbred; she 
 was mated with a quagga and produced a hybrid foal. She was 
 then mated to a Thoroughbred stallion and produced a foal with 
 stripes. In spite of the fact that Darwin knew that frequently horses 
 had both shoulder stripes and leg stripes, and that mules with leg 
 stripes were known to occur, he coupled this Morton case with the 
 erroneous beliefs of dog breeders and gave the theory in question 
 the powerful support of his authority. The theory has been com- 
 pletely disproved by Ewart, who has clearly shown it to have been 
 
 Purebred Poland China sow. 
 FIG. 29. Contrast this picture with the photograph of the Piney-Woods sow. 
 
 a manifestation of inheritance. Horses, asses, and other equine stock 
 have a common origin. With our present knowledge of Mendel's law, 
 which was unknown to Darwin, we can understand much more readily 
 that the appearance of stripes in horse stock is more likely due to the 
 unexpected appearance of a recessive character than to any residu- 
 ary effect of any impregnation on the chromosomes of the female 
 germ cells. Such a theory is utterly impossible if we accept the 
 known facts regarding the chromosomes and their behavior. 7 
 
 Crosses most readily demonstrate the operations of Mendelism, 
 and the more violent the cross the more astonishing are the results. 
 It often happens that the cross of ass and mare brings to the surface 
 characters common to the horse ancestors of the distant past. An- 
 other interesting case is seen in crossing certain breeds of hogs, re- 
 
 7 See pages 5-8. 
 
Essentials of Animal Breeding. 
 
 35 
 
 suiting in young which have the longitudinal stripes characteristic 
 of the young wild boar. 
 
 MATERNAL IMPRESSIONS. 
 
 A famous ancient classic is the bargain which Jacob made with 
 his father-in-law Laban, and since its historic consummation some 
 breeders of cattle have believed that the presence of objects of strik- 
 ing form or color before the eyes of the female at the time of con- 
 ception have an influence on the characteristics of the progeny. So 
 far as the Biblical case is concerned, the writer's impression is that 
 Laban was not so skilled in the animal husbandry of his day as was 
 
 Purebred Duroc-Jersey boar. 
 
 FIG. 30. Quick results can be obtained by using such, males on native sows, or an 
 investment may be made in one or two purebred sows, from which an entire herd of 
 purebreds is soon at hand. 
 
 his crafty son-in-law, and judging by Avhat we know to-day of the 
 livestock of Palestine, it would have been far more remarkable if a 
 large proportion of the calves had not been speckled and spotted. 8 
 A much more modern case is that of McCombie, of Tilly four, one of 
 the early Scotch improvers of Aberdeen- Angus cattle, who is reported 
 to have believed that he could increase the proportion of black cattle 
 in his herd by having his barns and fences painted black. The red 
 color was comparatively common among Angus cattle a hundred 
 years ago, and breeders were constantly culling out that color. From 
 what we now .know of the action of the chromosomes, it was selection 
 and not the color of McCombie's barns that made the Angus cattle 
 "black and all black." Even to-day an occasional red Angus calf 
 appears, as we would expect to happen according to the Mendelian 
 
 8 See Genesis xxx : 25-43. 
 
36 Farmers' Bulletin 1167. 
 
 law of inheritance. If the color before the cow's eyes at the time of 
 service had anything to do with the color of the calf, the red barns 
 of the Corn Belt would long since have had an astonishing effect on 
 our American Angus cattle. 
 
 Even monstrosities in animals are probably the appearance of 
 some long-submerged character, brought up out of the. stream of 
 inheritance by some peculiar combination of the hereditary ele- 
 ments. Certain animals and certain strains produce monstrosities 
 more often than others. Many of these can be brought out readily 
 by intensive inbreeding. 
 
 The pregnant mother, whether of the human or of the animal 
 family, should be an object of the utmost solicitude and should 
 receive the most thoughtful, tender care. She is engaged in a double 
 duty. The development of the young creature in her body taxes 
 
 How Good Breeding Affects Size. 
 
 FIG. 31. The large animal is a yearling Aberdeen- Angus steer. The smaller one is a 
 three-year-old Piney-Woods steer. The difference between the two is due almost 
 entirely to difference in breeding. 
 
 both bodily strength and nervous organization. We must not for- 
 get, however, that there is no direct connection of circulation or 
 nervous system between the mother and the fetus. Therefore the 
 fetus can not be affected by what the mother sees or hears. Acci- 
 dents to the mother, however, such as sudden strains, falls, etc., 
 may have effects resulting in the serious injury or death of the 
 young. These, again, are not due to heredity, no matter what the 
 effect on the young may be. 
 
 CONCLUSIONS. 
 
 The writer does not presume by any means to believe that his 
 effort will succeed in removing completely from the minds of men 
 their fallacious beliefs concerning animal inheritance, but he does 
 hope that he may have some influence in causing those who breed 
 animals to look more to nature herself and to tlie operation of her 
 
Essentials of Animal Breeding. 
 
 37 
 
 laws for the explanation of the 'facts which they observe and not 
 try to explain them as due to supernatural causes. To summarize 
 very briefly, let us bear in mind the following fundamental facts : 
 
 1. All animal forms on the earth have developed gradually from 
 lower forms by very slow changes. This is the process known as 
 evolution. 
 
 2. The young animal starts on its career when two bits of heredi- 
 tary material (germ plasm) unite, one from the female (the egg) 
 and the other from the male (the sperm). When the union is com- 
 plete, the sex, identity, and individuality of the animal are settled. 
 Chance plays a most important part in determining these factors. 
 
 3. From now on the fate of the animal depends on its nourish- 
 ment and environment. 
 
 Why Cloud a Boy's Dreams With This Kind of Stock? 
 
 FIG. 32. Give the youngsters well-bred pigs, calves, sheep, and chickens, and they will 
 be much more likely to stay on the farm and become producers of useful, profitable 
 animals to the advantage of their own pocketbooks and the wealth of the Nation. 
 
 4. The breeder can do much to bend the operations of the laws 
 of chance to his own ends by careful selection of breeding stock. 
 u Breed the best to the best." 
 
 5. Next to selection the best means at the command of the breeder 
 to fix type in his animals is inbreeding. It is a powerful tool, but 
 a dangerous one in unskillful hands. Inbred sires are more im- 
 pressive as a rule than sires which are not inbred. 
 
 6. Nature does not work lawlessly. Occurrences attributed to 
 supernatural means can be more rationally explained as a manifesta- 
 tion of some operation of a law of heredity. 
 
 If a breeder has a clear conception of these facts, he can usually 
 explain by one or the other nearly every occurrence which he may 
 observe. The clearer he thinks on these subjects the more successful 
 he will be as a breeder. 
 
38 Farmers' Bulletin 1167. 
 
 PUBLICATIONS OF UNITED STATES DEPARTMENT OF AGRICUL- 
 TURE RELATING TO BREEDING AND RAISING LIVESTOCK. 
 
 AVAILABLE FOR FREE DISTRIBUTION BY THE DEPARTMENT. 
 
 Breeds of Sheep for the Farm. (Farmers' Bulletin 576.) 
 
 Breeds of Beef Cattle. (Farmers' Bulletin 612.) 
 
 Breeds of Draft Horses. (Farmers' Bulletin 619.) 
 
 Colts: Breaking and Training. (Farmers' Bulletin 667.) 
 
 Breeds of Swine. (Farmers' Bulletin 765.) 
 
 Dairy Calves and Young Dairy Stock. (Farmers' Bulletin 777.) 
 
 How to Select a Sound Horse. (Farmers' Bulletin 779.) 
 
 Standard Varieties of Chickens: I. The American Class. (Farmers' Bulletin 
 
 806.) 
 
 Farm Sheep Raising for Beginners. (Farmers' Bulletin 840.) 
 Breeds of Dairy Cattle. (Farmers' Bulletin 893.) 
 Standard Varieties of Chickens : II. The Mediterranean and Continental Classes. 
 
 (Farmers' Bulletin 898.) 
 
 Breeds of Light Horses. (Farmers' Bulletin 952.) 
 Standard Varieties of Chickens : III. The Asiatic, English, and French Classes. 
 
 (Farmers Bulletin 1052.) 
 
 PUBLICATIONS RELATING TO LIVESTOCK IMPROVEMENT. 
 
 Castration of Pigs. (Farmers' Bulletin 780.) 
 
 Production of Baby Beef. (Farmers' Bulletin 811.) 
 
 Livestock Classification at County Fairs. (Farmers' Bulletin 822.) 
 
 Swine Management. (Farmers' Bulletin 874.) 
 
 Dehorning and Castration of Cattle. (Farmers' Bulletin 949.) 
 
 Cooperative Bull Associations. (Farmers' Bulletin 993.) 
 
 Judging Beef Cattle. (Farmers' Bulletin 1068.) 
 
 Growing Beef on the Farm. (Farmers' Bulletin 1073.) 
 
 Castrating and Docking Lambs. (Farmers' Bulletin 1134.) 
 
 "Better Sires Better Stock" booklet. 
 
 " Which Way Is Your Livestock Going? " poster. 
 
 " Purebred Sires and Herd Improvement " poster. 
 
THIS BOOK IS DUE ON THE LAST DATE 
 STAMPED BELOW 
 
 AN INITIAL FINE OF 25 CENTS 
 
 WILL BE ASSESSED FOR FAILURE TO RETURN 
 THIS BOOK ON THE DATE DUE. THE PENALTY 
 WILL INCREASE TO 5O CENTS ON THE FOURTH 
 DAY AND TO $1.OO ON THE SEVENTH DAY 
 OVERDUE. 
 
 LD 21-100>-8,'34 I 
 
Gaylord Bros. 
 
 Makers 
 
 Syracuse, N. Y. 
 PAT. JAN. 21, 1908 
 
 
 UNIVERSITY OF CALIFORNIA LIBRARY