DAIRY CATTLE.

Shannon News, 30 October 1923, Page 3

DAIRY CATTLE.

PRINCIPLES OF BREEDING

If certain desirable characters are to. be perpetuated and retained in the flock or herd, line-breeding, which is a modified form of in-breeding, is absolutely essential. But it takes a master hand, one who knows - the weaknesses of the strain or the family he is breeding, tQ apply it in its entirety. Line-bred animals are enormously prepotent, possessing half the ancestry, and almost certain to transmit to their progeny very fully. At the same*time, in inexperienced hands it. may be followed by terrible disas- j ter. However, breeders can take comfort in the assurance that in-breeding I does not lead to loss of vigour and fertility. We select for colour and other points, but if we select, for fertility and vigour as well, we may be assured that these qualities will certainly be actually intensified by inbreeuing; just as much, in fact, as they can be reduced by in-breeding from animals which have not gpt them, to start with. Admitted that few breeding animals are fully fertile, and still fewer both fertile, and vigorous,, the breeder .will not ha,ve an easy task to avoid the common defects of inbreeding. The idea is worth keeping prominently before us that these evils are by no means inevitable. Another point to he remenihered is the common failure to realise 'that for practical purposes potency of ancestry mainly exists in "nearby" generations and not in hack numbers. This is a matter of practical importance in considering pedigree, and undue study of ancestral lines some ten generations back is. "pathetic." This does not imply that these longback pedigrees are to be despised. The point is rather that the so-called foundation is not one in reality, but merely a starting point, because, in fact, it is the "top" rather than, the bottom that counts. Though this may seem heretical, as one likes to* point right back to some • great progenitor, yet the average influence of 'each individual shows little effect a ft er a few generations. As an example: At one generation hack this influence is 25 per cent., but at ten "the average influence of the single ancestor is something like one in a million of the total influence of heritage. There are .qualifications, however, to this, of course, where individual merit stands out and towers 'above the average, and where close in-bree*ding is practiced the influence is multiplied, but even then six generations wipe out the individual influence of an ancestor. The value of the "top" being so great, we can understand the insistence laid on using animals which have been well proved when purchases aire made.

OldJ dairy animals are, therefore, to be . recomended if they are still fertile, and. old females have the additional merit of being cheaper and coming into* profit quicker than very young ones. To put a new young* sire into full service is entirely wrong, but when tested he should be kept so long) a« successful. The practice of paying enormously high prices for young stock is a Ihuge gamble, but it is strange the preference that is shown for them, by the average breeder. The breeder only able to start in «t small way will produce just as good, or better stock by purchas.ing sound old stock.—" The Dairy."