BREEDING LIVE STOCK ON THE FARM CATTLE.

Otago Witness, Issue 2685, 30 August 1905, Page 6

BREEDING LIVE STOCK ON THE FARM CATTLE.

The breeding of live stock on the farm Is a subject so simple in some respects that it may be compared to a shallow pool in which a child might wade. In other respects it is a great deep sea, which will cover a giant at tli9 very first plunge. Among the shallow pJaces may be mcludecl Uie general ojoeiatiou of tie law

that like produces h ! -:<_. that heredity fa strong m proportion to the purity and ' intensity of the breeding, and that usually tiio influence of the parents of the recent; ancestry is greater in transmission than that, of the ancestry more remote. Among the great deeps are the influences which govern variation, atavism, and ,sex in transmission. To these may be added the influence of a previous impregnation and t'ho laws that control mtrauterine development. Before the breeder has proceeded iar in the study of the latter class of subjects, ho will be ready to conclude that the domain before him is perplexing, that it is broader than the sea, and Hiat many of its pathways are fo dark that they may be fitly compared with underground passages into which the light Las never shone. In these tacts the explanation is found that breeders who have made a great success of their work are fewer in number than legislators who have made a great success of theirs : notwithstanding that the rules that govern transmission, such as will lead to a fair measure of success in the work, are so few and simple that a youtih. even can understand and) apply them.

The essential laws that govern breeding are three in number — viz., the law that like produces like in transmission; that like does not always produce like on the law of variation ; and the law of atavism. No one of these laws is so unvarying in its action that the exact character of th 9 transmission can be certainly predicted beforehand. But it would probably be correct to say that the first of the three is apparently the most uniform in its action, and that the last is the least uniform.

The law that like produces like isthe great sheet-anchor of the breeder. Were it not no substantial progress could be made. Breeding would b-a absolutely a. game of chance. The principles tihafc govern this and every ether form ot transmission are doubtless inflexible and unvarying, buc the influences that determine the precise nature of the action of these principles are so many and oftentimes so little understood that absolute uniformity in results cannot be looked for.

It would seem correct to say, however, that uniformity in results may be looked r'or in proportion as transmission is potent. Transmission is potent in proportion to the prepotency of one or both parents. It will be prepotent according to the purity of the breeding, to its duration, and to its .intensity, and also in proportion to the inherent vigour of the parents. In tfes first fact is found a great argument for the invariable use of purebred sires, even when grading up. In the second fact are found the reasons why sires that have come from a long line of pure ancestry are to be preferred. In the third fact are found the reasons why males chosen from families judiciously bred in line are usually more prepotent than other purebred sires of the same breed. And in tfc.3 fourth fact lies the wisdom of giving much attention to indications of bodily vigour in a, sire as a probable guarantee of increased prepotency. But in choosing sires the danger lies in too much intensity of breeding, which must be shunned, because of the evils resulting from the same. Individual vigour in a marked degree is one of the moso important evidences that the intensity of breeuing lias not, in that instance at least, been carried too far.

| Theoretically equal prepotency on the part of both parents would be more de- ; sirable than superior prepotency on the ' part of one, providing the individuality jof botih were equally good. But in actual praciToß "little attention relatively is given , to prepotency in the female as compared ! with the prepotency of the male, and very 1 properly so, since the individual male, through the number of Ms progeny, exercises a. fsr greater influence on tlTe herd as a whole than the individual femalo A'iewed from this standpoint the importance of individual prepotency in the female wanes. In fact, if such pre- ! potency were antagonistic to the results sought from using a prepotent male the absence of prepotency on the part of the tema'e is to be preferred to its presence, since in proportion as it was weak or .absent in the female just in that proportion "would added improvement in the progeny come through the male. TJie second law of breeding — viz., that like does not always produce like on the law oi variation — furnishes the reason, but not the full explanation, as to why Tub progeny are not always like the ancestry. It might be supposed, on first thought, that because of tihe operation of the first law of breeding, the progeny would be an exact mean between the parents, when the individual furnishings of the latter differed. But such a result never follows, since the exact measure of the piepotency in the two is never exactly the s: me. Other influences which aii'eet variation are also usually present, such as pertain to different degrees of individual vigour at different ages and because of different management, in these facts is lound a partial reason for constantly recurring variations," but they do not account for all variations. An eminent authority on the subject writes: — "The constant variations that occur are not always to> be regretted. The law of variation may bring help to the breeder as well as the law that like produces like. If this former law had no existence, the limit of improvement would soon become fixed. The progeny never become better than the parents ; hence a level would soon ba reached beyond which improvement coupled not go. Tibs result would be paralysing to the effort of the ambitious breeder, t who now realises that no limit lias been set beyond which improvement may not bo carried. But zealously watcli-

Eaiasrs of Poultry should use Nnraro akd ' Blair's Game and Poultry Meal, which i» composed of the best ground bones and shells, specially prepared to meet the requirements of the fast-increasing poultry inchistiy. It is made up :n 34] b bags, at Is 9d each. Ask sous storekeeper i&i it,

ing for variations in- th£ lies of improvement, especially in well-bred animals, and ; ■using tbem judiciously in breeding, a J highisr level of attainment is reached, and 1 thus the stepping stones Gf advancement j may be climbed by the breeder who aims j to' reach still higher levels. . . . But | t'Bere is another class of variations gene- j rally referred* to as 'spontaneous,' 'sudden,' ; ■or 'extraordinary.' These variations come i ■unexpectedly. -They are more or less ■ -marked and' significanffc in character. Tho j absence of horns in a horn- bred is a cas-o . in point. Without the aid of man these j cannot perpetuate tlusmselves, they are so ! few in number. They soon become k>sfc again, obliterated, because of the littlo influence they exert, owing to the limited number of instances in which they o-ccur. Man has utilised these in the instance cited, but usually it is not desirable to perpetuate them ; hence they do not call for much attention on tho part of the breeder. Jt is with ordinary variations that he is chiefly ccaicerued, and ihe •Should show much decision with reference to the ' "discarding of specimens for breeding when : the trend of variation is downward, and in saving those for future breeding when, it is upward. It is fai more frequently downward than upward, in unison with the natural trend of Jmioan actions in the absence of sufficiently potent counteracting moral influences. This do 23 not of necessity imply that the causes are the same in j the two classes of instances. But that the j tTend of variation is more frequently down- I •ward than upward \ dees not mean thab more animals must bo -sacrificed in the herd than are retained in it, if improvement is to be continuous.' 1 'Atavism, the third law of breeding, : S*-efers •t& animails • born into the herd ! possessed >f characters which belong to. ancestors more or less remote, and which if is not dissirable to perpetuate. The white colouring of shorthorns, the occur- I rence of * tbe white belt on galloways, the ' occasional red colour on Angus cattle, and splashes -di white on Berkshire swine on I othe.' parts than the forehead, feet, and 1 tip •>£ tail furnish illustration?. These are j usually of less frequent occurrence with ! each succeeding generation; hence, with ! due' vigilance in discarding animals thus j characterised for breeding us,es, the instances of atavic transmission may be ex- ' pected to grow less and less remote in the future. They should finally disappear. It is roi meant that the atavic transmission ! ■will cease to be operative, but that the transmission of these undesirable characters will <3iis>appear.

A grade, strictly speaking, is this offspring of a purebred and an animal of common or mixed breeding 1 . -Either the mate or the female may be pure, but in practice the male is usually pure and the female of mixed blood. The reasons for breeding tihuis will be at once apparent ■when ii- is remembered that to mate pure females with males of mixed blcod would foe to lessen the value of the offspring. It- would, of course, bo grading downward rather than upward. The importance of using livxobreA males and cf good quality ■will ha at once apparent to those who .understand the principles that govern breeding.

Purebred sires are prepotent; that is, they have much power to produce characters in "the progeny such as they them--selves possess, because they are purely ftred. This comes from a constant accumulation of similar bleed units through continued purs breeding. They will have this power in proportion to the length of tite period during -which, their ancestors' have •baen purebred, to the excellence of the animals in the near ancestry, to the closeness of breeding in the saxae, and to the strength of the inherent ruggedness of the constitution and bodily vigour of thi9 animal. A grade male cannot transmit has own good projjerties with certainty because of the absence of concentration of similar blood units, arising from the mixed character of his breeding. He cannot be expected: to transmit characters with any degree of fixedness which are not stable even with him, since time Itas not been given to make them so by breeding within straight blood' lines, iind the more mixed the breeding, especially of the immediate ancestry, the less uniform is the transmis sion of* character by such a male. In up-grading the foundation females are Visually much mixed in breeding. This cloes not render them objectionable for such a use, providing they have good and lugged frames. In f-iet, the more diverse the blood; elements lJusy possess — that is, the more mixed the character of the breeding — the more quickly will improvement be effected throxigh the 'use of a prepotent male, as the- resistant power to tie improvement effected by the male in the ■jxpogeny decreases in the female with increase in. tine mixing of tliu blood elements which she possesses. When good purebred bulls are used from tlie same breed in up-grading, improvement is rapid and continuous until that

point is reached when, for practical uses, the progeny have reached the level of the breed front which the sires tvere chosen. It is taken for granted that the feeding and management generally which accompany such breeding are in the main correct. Wihem purebred animals ef equal purity and strength aa*e mated, the. piogeny will poisbess approximately 50 per cent, nf the bleed units of each. But in up-grading this does not follow. It cannot. The pure male has- much more power to effect change* than the mixed female hrs to resist- the same : consequently tlie progeny will bear a much closer resemblance to the male than to ths female. This preponderance in semblance will hs in proportion as the power in the male, because of his pai'ity in breeding, to transmit X>ioperties .exceeds that of the female of mixed breeding to transmit the same. Tho sum of the properties transmitted by the male will be much greater than the sum of the proper! aes transmitted by the female.