Chapter VII · ToC
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CHAPTER VII.ToC
In-and-in Breeding.
It has long been a disputed point whether the system of breeding in-and-in or the opposite one of frequent crossing has the greater tendency to maintain or improve the character of stock. The advocates of both systems are earnest and confident of being in the right. The truth probably is, as in some other similar disputes, that both are right and both wrong—to a certain extent, or within certain limits.
The term in-and-in is often very loosely used and is variously understood; some, and among these several of the best writers, confine the phrase to the coupling of those of exactly the same blood, i.e. brothers and sisters; while others include in it breeding from parents and offspring, and others still employ the term to embrace those of more distant relationship. For the latter, the term breeding in, or close breeding, is deemed more fitting.
The prevalent opinion is decidedly against the practice of breeding from any near relationships; it being usually found that degeneracy follows, and often to a serious degree; but it is not proved that this degeneracy, although very common and even usual, is yet a necessary consequence. That ill effects follow in a majority of cases is not to be doubted, but this is easily and sufficiently accounted for upon other grounds. In a state of nature animals of near affinities interbreed without injurious results, and it is found by experience that where domesticated animals are of a pure race, or of a distinct, well defined and pure breed, the coupling of those of near affinities is not so often followed by injurious effects as when they are crosses, or of mixed or mongrel origin, like the great majority of the cattle in the country at large. In the latter case breeding in-and-in is usually found to result in decided and rapid deterioration. We should consider also that few animals in a state of domestication are wholly free from hereditary defects and diseases, and that these are propagated all the more readily and surely when possessed by both parents, and that those nearly related are more likely than others, to possess similar qualities and tendencies.
If such is to be regarded as the true explanation, it follows that the same method would be also efficacious in perpetuating and confirming good qualities. Such is the fact; and it is well known that nearly all who have achieved eminence as breeders, have availed themselves freely of its benefits. Bakewell, the Messrs. Colling, Mr. Mason, Mr. Bates and others, all practiced it. Mr. Bates' rule was, "breed in-and-in from a bad stock and you cause ruin and devastation, they must always be changing to keep even moderately in caste; but if a good stock be selected, you may breed in-and-in as much as you please."[20] Bakewell originated his famous sheep by crossing from the best he could gather from far or near; but when he had obtained such as suited him, he bred exclusively from within his own. As in all breeding from crosses, it was needful to throw out as weeds, a large proportion of the progeny, but by rigidly doing so, and saving none to breed from but such as became more and more firmly possessed of the forms and qualities desired, the weeds gradually became fewer, until at length he fully established the breed; and he continued it, and sustained its high reputation during his life by in-breeding connected with proper selections for coupling. After his death, others, not possessing his tact and judgment in making selections, were less fortunate, and in some hands the breed degenerated seriously, insomuch that it was humorously remarked, "there was nothing but a little tallow left." In others it has been maintained by the same method. Mr. Valentine Barford of Foscote, has the pedigree of his Leicester sheep since the day of Bakewell, in 1783, and since 1810, he has bred entirely from his own flock, sire and dam, without an inter-change of male or female from any other flock. He observes "that his flock being bred from the nearest affinities—commonly called in-and-in breeding—has not experienced any of the ill effects ascribed to the practice." W.C. Spooner, V.S., speaking of Mr. Barford's sheep says, "His flock is remarkably healthy and his rams successful, but his sheep are small."
Mr. Charles Colling, after he procured the famous bull Hubback, selected cows most likely to develop his special excellencies, and from the progeny of these he bred very closely. From that day to this, the Short-horns as a general thing, have been very closely bred,[21] and the practice has been carried so far, the selections not always being the most judicious possible, as to result in many cases in delicacy of constitution, and in some where connected with pampering, in sterility.[22]
Col. Jaques, of the Ten Hills Farm near Boston, imported a pair of Bremen geese in 1822. They were bred together till 1830, when the gander was accidentally killed. Since then the goose bred with her offspring till she was killed by an attack of dogs in 1852. Great numbers were bred during this time, and of course there was much of the closest breeding, yet there was no deterioration, and in fact some of the later ones were larger and better than the first pair.
The same gentleman also obtained a pair of wild geese from Canada in 1818, which with their progeny were bred from without change until destroyed by dogs with the above named in 1852. They continued perfect as at first.
Among gregarious ruminating animals in a state of nature, all who associate in a herd acknowledge a chieftain, or head, who maintains his position by virtue of physical health, strength and general superiority. He not only directs all their movements but is literally the father of the herd. When a stronger than he comes, the post of chieftain and sire is yielded, but in all probability his successor is one of his own sons, who in turn begets offspring by his sisters. The progeny inheriting full health, strength and development, the herd continues in full power and vigor,[23] and does not degenerate as often happens when man assumes to make the selections, and chooses according to fancy or convenience. The continuance of health, strength and perfect physical development is believed to depend on the wisdom of the selection, upon the presence of the desirable hereditary qualities, and the absence of injurious ones, and not upon relationship whether near or remote.
It has fallen within the observation of most persons that in the human race frequent intermarriages in the same family for successive generations often tend to degeneracy of both mind and body; size and vigor diminishing, and constitutional defects and diseases being perpetuated and aggravated; but neither in this case is the result believed to be a necessary and inevitable consequence. Else how could it be, that Infinite Wisdom, whose operations are ever in accordance with the laws of his own institution, in originating a "peculiar people," chosen to be the depositories of intellectual and physical power, wealth and influence, and who, in spite of oppression without parallel in the world's history, have ever maintained the possession of a goodly share of all these,—would have allowed their first progenitor, Abraham, to marry his near kinswoman Sarah, a half sister, niece or cousin, and Isaac their son to wed his first cousin Rebecca, and Jacob who sprang from that union, to marry first cousins, and their offspring for long generations to intermarry within their own people and tribes alone? At a later period, marriages within certain degrees of consanguinity were forbidden by Divine authority, but not until the peculiar race was fully established, and so far multiplied, as to allow departure from close breeding without change of characteristics, and not improbably the prohibition was even then based more upon moral reasons, or upon man's ignorance or recklessness regarding selection, than upon physical law.
Such laws exist among us at present, and it is well they do, inasmuch as for the reasons already given there is greater probability of degeneracy by means of such connections than among those not so related by blood. But they present an instance of the imperfection of human laws, it being impossible for any legal enactments to prevent wholly the evil thus sought to be avoided. It would be better far, if such a degree of physiological knowledge existed and such caution was exercised among the community generally, as would prevent the contraction of any marriages, where, from the structure and endowments of the parties, debility, deformity, insanity or idiocy must inevitably be the portion of their offspring whether they are more nearly related than through their common ancestor, Noah, or not.
If we adopt Mr. Walker's views, it is easy to see how parents of near affinities may produce offspring perfect and healthy, or the reverse. He holds, that to secure satisfactory results from any union, there should be some inherent, constitutional, or fundamental difference; some such difference as we often see in the human family to be the ground of preference and attachment; as men generally prefer women of a feminine rather than a masculine type. All desire, in a mate, properties and qualities not possessed by themselves. Now assuming as Mr. Walker holds, that organization is transmitted by halves, and that, in animals of the same variety, either parent may give either series of organs, we can see in the case of brother and sister that if one receives the locomotive system of the father and the nutritive system of the mother, and the other the locomotive system of the mother and the nutritive system of the father, they are essentially unlike, there is scarcely any similarity between them, although, as we say, of precisely the same blood; and their progeny if coupled might show no deterioration; whereas, if both have the same series of organs from the same parents, they would be essentially the same, a sort of quasi identity would exist between them, and they are utterly unfit to be mated. There might be impotency, or barrenness, or the progeny, if any, would be decidedly inferior to the parents; and the same applies, more or less, to other relatives descended from a common ancestry, but more distant than brother and sister. Mr. Walker also holds that where the parents are not only of the same variety but of the same family in the narrowest sense, the female always gives the locomotive system and the father the nutritive; in which case the progeny is necessarily inferior to the parents.
A careful consideration of the subject brings us to the following conclusions, viz:
That in general practice, with the grades and mixed animals common in the country, close breeding should be scrupulously avoided as highly detrimental. It is better always to avoid breeding from near affinities whenever stock-getters of the same breed and of equal merit can be obtained which are not related. Yet, where this is not possible, or where there is some desirable and clearly defined purpose in view, as the fixing and perpetuating of some valuable quality in a particular animal not common to the breed, and the breeder possesses the knowledge and skill needful to accomplish his purpose, and the animals are perfect in health and development, close breeding may be practiced with advantage.