Breeder (animal)

“ Breeders feel no doubt on this head; ask a man who has long reared Shorthorn or Hereford cattle, Leicester or Southdown sheep, Spanish or Game poultry, tumbler or carrier-pigeons, whether these races may not have been derived from common progenitors, and he will probably laugh you to scorn. The breeder admits that he may hope to produce sheep with finer or longer wool and with better carcases, or handsomer fowls, or carrier-pigeons with beaks just perceptibly longer to the practised eye, and thus be successful at an exhibition. ”

“ As cross-bred animals are generally of large size and vigorous, they have been raised in great numbers for immediate consumption. But for breeding they are found to be utterly useless; for though they may be themselves uniform in character, when paired together they yield during many generations offspring astonishingly diversified. The breeder is driven to despair, and concludes that he will never form an intermediate race. ”

“ But the breeders cause every visible part of the body to vary as seems good to them, and within the last fifty years they have really brought about very considerable changes in many breeds. Their method of procedure is carefully to select for breeding those birds which already possess a faint beginning of the desired character. Domesticated animals have on the whole a higher degree of variability than wild species, and the breeder takes advantage of this. ”

“ If even in such minute particulars as these, hereditary transmission may be distinctly seen, it becomes the breeder to look closely to the "like" which he wishes to see reproduced. Judicious selection is indispensable to success in breeding, and this should have regard to every particular—general appearance, length of limb, shape of carcass, development of chest; if in cattle, the size, shape and position of udder, thickness of skin, "touch," length and texture of hair, docility, &c., &c. ”

“ If the Japanese breeders were able to lengthen the tail-feathers of the cock to six feet, it can only have been because the determinants of the tail-feathers in the germ-plasm had already struck out a path of ascending variation, and this movement [50] was taken advantage of by the breeder, who continually selected for reproduction the individuals in which the ascending variation was most marked. For all breeding depends upon the unconscious selection of germinal variations. ”

“ Now we know of no facts which forbid us to suppose that could a breeder continue his operations indefinitely for any length of time—say for a few million years—he could convert the short-horned breed into a hornless breed; that he could go on and thicken the tail, could shorten the legs, get rid of the hind limbs altogether by a series of insensible gradations, and convert the race into forms like the Sirenia, or sea-cows. ”

“ These breeds are always produced in the same way. The breeder selects a pair, one or other, or both, of which present an indication of the peculiarity he wishes to perpetuate, and then selects from the offspring of them those which are most characteristic, rejecting the others. ”

“ To insure successful and beneficial crossing of distinct breeds, in order to produce a new and valuable variety, the breeder must have an accurate knowledge of the laws of procreation, and the varied influences of parents upon their offspring. All the breeds in this country are crosses, produced either by accident or design. Crossing does not necessarily produce a breed; but it always produces a variety, and that variety becomes a breed only where there is a sufficiency of stamina to make a distinctive race, and continue a progeny with the uniform or leading characteristics of its progenitors. ”

“ On careful inquiry it is found that all these, and the [Pg 348] many other artificial breeds or races of animals and plants, have been produced by one method. The breeder—and a skilful one must be a person of much sagacity and natural or acquired perceptive faculty—notes some slight difference, arising he knows not how, in some individuals of his stock. If he wish to perpetuate the difference, to form a breed with the peculiarity in question strongly marked, he selects such male and female individuals as exhibit the desired character, and breeds from them. ”

“ After commenting on these purely imaginary causes, I pointed out in 1832, as the two great flaws in Lamarck's attempt to explain the origin of species, first, that he had failed to adduce a single instance of the initiation of a new organ in any species of animal or plant; and secondly, that variation, whether taking place in the course of nature or assisted artificially by the breeder and horticulturist, had never yet gone so far as to produce two races sufficiently remote from each other in physiological constitution as to be sterile when intermarried, or, if fertile, only capable of producing sterile hybrids, &c. ”

“ The sheep-breeder can, however, avoid the effects of in-and-in breeding, and at the same time preserve the character of his flock, by seeking rams of the same breed, possessing, as nearly as possible, the characteristics which he wishes to preserve in his own flock. ”

“ It is free intercrossing which chiefly gives uniformity, both under nature and under domestication, to the individuals of the same species or variety, when they live mingled together and are not exposed to any cause inducing excessive variability. The prevention of free crossing, and the intentional matching of individual animals, are the corner-stones of the breeder’s art. No man in his senses would expect to improve or modify a breed in any particular manner, or keep an old breed true and distinct, unless he separated his animals. ”

“ The far too common practice is to purchase each boar required from a totally different herd, or from one of quite dissimilar breeding, with the result that there is not the slightest uniformity in the appearance or character of the herd, or of the mature animals when ready for market.
It is far too frequently forgotten that the chief value of a record of the pedigree is that by it one can trace the breeding of the animal's progenitors, and thus one is enabled to form some opinion of the probable produce—providing it is possible to learn the chief characteristics of the progenitors. ”

“ But the case would be quite different if the winning sire and dam came from the same old established herd in which the animals had been bred for generations on similar lines. It is this concentration of certain qualities in generation after generation which renders the pedigree animal so intensely prepotent, particularly when mated with animals of an ordinary character or not possessing concentrated breeding. ”

“ In-breeding is beyond all doubt the strongest weapon the dog breeder has, but it is a boomerang that is very apt to come back and knock its thrower in the head. In-breeding is the breeding together of the blood of one dog—mother to son, or brother to sister. ”

“ Now it has always been known that breeders could produce a race of markedly peculiar form or characteristics by selecting the individuals possessing this quality in the highest degree and breeding only from these. The breeder depends upon heredity, variation, and his selection of the individuals from which to breed. Similarly in nature new species have arisen through heredity, variation, and a selection according to the laws of nature of those varying in conformity with their environment. ”

“ He must, as far as possible, conform to the principles of the stock-breeder, whose object is to rear the finest horses, cattle or sheep. Amongst wild animals nature selects the fittest for continuing the race, and the wise breeder simply aids nature by selecting still more carefully the best animals. ”

“ A very large number of instances of this kind have been reported to me by well-known breeders of horses, cattle, pigs, dogs, and pigeons. Sometimes a breeder will fail to obtain offspring from a male and a female of known fertility whom he wishes to couple for some special reasons. The most celebrated living horse-breeder informed me 546that frequently a mare, which in other seasons with other stallions has proved fertile, may be coupled with a stallion likewise of proved reproductive potency, and will fail to be impregnated ”

“ It is not for us to determine the knotty point, but we may venture the opinion that the two first definitions of a cross-bred are not convincing to us, since in order to produce a cross-bred it is necessary to have a sire, or a dam, or both of defined breeds. Probably the most correct definition of a cross-bred animal is one bred from the mating of sire and dam of two distinct breeds, but the term is now loosely applied to an animal begotten by a sire or from a dam of pedigree breeding, the other parent being of no particular breed. ”

“ Among
domestic animals, on the other hand, mere survival is not enough. Where the breeder intervenes, propagation becomes the critical point. The breeder can use inferior cattle as draft animals. He favors some definite type for reproduction, but rejected individuals are not therefore destroyed. They may be put to some other use. Breeders selection has, as we shall come to see, the character of reproductive selection. What Darwin, for the most part, dealt with as natural selection, we shall find it better to call lethal selection. ”

“ Great care should be exercised in the selection of the males for breeding stock. Only the large and healthy animals of good color should be used and all others should be killed and their skins marketed, or the live altered animals sold for pets, while they are in good condition. Never allow a breeder to die of old age. Sell the pelts early and use young stock for the purpose.
While the animals do not always breed strictly true to color, the white markings may be greatly reduced and the general stock improved by selected breeding. ”

“ This strong tendency in crossed breeds to revert has given rise to endless discussions in how many generations after a single cross, either with a distinct breed or merely with an inferior animal, the breed may be considered as pure, and free from all danger of reversion. No one supposes that less than three generations suffices, and most breeders think that six, seven, or eight are necessary, and some go to still greater lengths. ”

“ As breeders of domestic animals, when they choose certain varieties in preference to others to breed from, speak technically of their method as that of 'selecting,' Mr. Darwin calls the combination of natural causes, which may enable certain varieties of wild animals or plants to prevail over others of the same species, 'natural selection.'
A breeder finds that a new race of cattle with short horns or without horns may be formed, in the course of several generations, by choosing varieties having the most stunted horns as his stock from which to breed; ”

“ Into this they will proceed of themselves when they are ready to perform their allotted act of reproduction, and the breeder awaiting his opportunity, places a net at the mouth of the race and frightening them in, selects such as are ready for manipulation.
When in a perfectly ripe condition, the eggs lie free in the ovaries in the abdomen, and may be extruded by a gentle pressure downward along the sides of the fish. ”

“ The degree of fecundity or lack of fecundity between different species varies in extraordinary and inexplicable fashion in different families of mammals. In the horse family, for instance, the species are not fertile inter se; whereas among the oxen, species seemingly at least as widely separated as the horse, ass, and zebra—species such as the domestic ox, bison, yak, and gaur—breed freely together and their offspring are fertile; the lion and tiger also breed together, and produce offspring which will breed with either parent stock ”

“ The breeder who wishes to combine fancy and utility properties in any kind of live stock must breed only from specimens that are meritorious in both directions, selecting much more carefully than when breeding for one class of properties. ”

“ The origin of the domesticated breeds is ascribed by Darwin, Blyth and other naturalists to the Bankiva fowl, much stress being laid on the comparative want of fertility in the hybrids produced between this species or the domesticated breeds and the other three forms of wild Galli, but it is probable that this want of fertility was due in great part to the unnatural conditions under which the parent and offspring were placed, as, if bred under more natural conditions, there is no difficulty in rearing these hybrids or in breeding from them with the domesticated varieties. ”

“ But neither in the case of a breed which has been contaminated by a single cross, nor when, in the attempt to form an intermediate breed, half-bred animals have been matched together during many generations, can any rule be laid down how soon the tendency to reversion will be obliterated. It depends on the difference in the strength or prepotency of transmission in the two parent-forms, on their actual amount of difference, and on the nature of the conditions of life to which the crossed offspring are exposed. ”

“ Line-breeding is a systematic form of breeding which preserves the excellence and characteristics of the parent stock. In other words, it perpetuates the blood of both sire and dam so that it is not eventually lost as is the case in cross-breeding. ”

“ All breeding is founded on the principle, that like begets like. This is, however, liable to some exceptions, and is much more generally true when breeding down than when breeding up. If two animals (which can never be exactly similar in all respects) are requisite to the perpetuation of the species, it necessarily results, that the progeny must differ in a more or less degree from each parent. ”