CONSTITUTIONAL DECLINE AND IN-BREEDING.

King Country Chronicle, Volume VII, Issue 540, 8 February 1913, Page 6

CONSTITUTIONAL DECLINE AND IN-BREEDING.

USING AND ABUSING CLOSE MATING. It is very probable that the delicate constitution possessed by considerable numbers of the ordinary stock, of the country is due to in-breeding, or a system which is carried on, not, in most cases, on any fixed principle or with any definite object in view, but simply through force of circumtance i or, perhaps, want of thought. Ori many farms a good, useful bull is purchased at what is considered a fairly big price, and the purchaser is anxious to make the most of him, and is used in the herd too long. His own stock come round in due courEO, and the farmer cannot afford to keep two bulla and want to get a bit more out of the old one, so the bull is often put to his own daughters, or perhaps a useful youngster may be saved and kept for use in the herd and be bred to his own sisters. Onca in a way this kind of thing may not do much harm, but it often happens that this sort of incestuous mating is carred on from time to time, and the constitution of theistock naturally becomes impaired. In the breeding of pedigree stock in breeding may be carried on up to cer tain limits for a certain .definite purpose, but in the breeding of ordin ary commercial stock there is no justification at all for pursuing that system. The object of all breeders of store stock should be to endeavour to obtain robust constitutions. Dairy farmers require stock that can stand our changeable climate without constantly taking colds and chills, and that can stand high feeding, or, for that matter, if feed is short, can keep their backs up When on short rations, and that can digest and assimilate their food in a proper manner and turn it to good accounti Weasel y stock can never do this, and as inbreeding, if carried too far, is bound to produce weakly stock breeders should be careful to use as much as possible sires that are unrelated to their own stock. The pioneer breeders Were limited in their choice of sires. There were only a few herds that they could draw on for fresh blood, and even then they were in many instances closely allied to their own; but then their own stock was hearty and vigorous to begin with, and they carried on the principles of in-breeding with a definite object in view, viz., to fix type and characteristics. With the nam ber of purebred herds in existence at the present day, and with the types and characteristics of the different breds already fixed, there is no necessity or excuse for carrying on any indefinite system of in-breeding.

Good animals of any type can now be bought at a reasonable • price to suit the requirements of any herd, and to sacrifice robustness of constitution in the young stock just to save a few epounds in the purchase of a fresh sire is a penny wise and pound foolish poilcy. It must alwavs be borne in mind that if a herd of any kind has any particular defect, in-breeding ia sure to bring out that defect more prominently in each generation. In addition to that, the results of inbreeding are generally infertility and general weakness. Calves are born into the world that cannot stand their own mother's milk,and scour and die. Som9 are born ricketty and never come to maturity; others are always wanting physic in sume way or another. Size, too, is very often sacrificed by inbreeding, and with regard to the keep ing up of size in either a herd or flock, fresh blood from time to time is bound to play an important part. A wellknown sheep breeder once told the writer that the only way he could maintain a certain standard of size in his flock was by introducing into his flock every year just half a scor« or so, of ewes from other flocks, and he considered j that this introduction of fresh blood on the female side as well as on the male side was a very considerable factor in maintaining the size and constitution of his flock. And in mentioning this, the same principle applies equally in the case of sheep or horses as to cattle. If a flock is too closely bred for some length of time, size and constitution are both lost. Thus it is that in many pedigree flocks where it is thought that type must come before everything in-breeding is carried on to a great extent, and we often see some of our purest-bred flocks consist of sheep that are line in bone and with small frames, delicate in constitution, find ing no favour with farmers. Type in purebred stock is, of course, of the utmost importance, but by skilful it need not be lost by an occasional change of blood from another flock equally as well bred. It is generally thought that an inbred sire is almost always prepotent < to a great degree and one moat desirable. In the case of horses, the writer haß known many instances where such a sire has been so. But, on the other ] hand, in-bred bulls have been in many cases dismal failures and their produce not worth rearing. Having once fixed a certain standard or type by a system of in-breeding, it must be a case of careful selection and skilful mating to keep up that standard, but there is no necessity nowadays for selecting and mating only, closely related cattle. There is a wide range, and plenty of animals can be found in other herds, eiither unrelated or, at any rate, very distantly related, that will answer the purpose for which they are required. Then, again, it is Bometimes argued that in-breeding can be indulged in with impunity, provided the most careful selection is made in |the mating of the animals, that is to say, [by b>ceding only from those that show signs of the most robust'constitutions and that have no defects of any kind. That theory may !be all very well for a time, but what a constant weeding out there must be; so much so, that a herd bred on these lines can never increase, but sooner or later ihuss

the time is bound to come when, from sterility, weakness and their causeß, the animals fit to breed from become fewer every year and tho greater. In-breeding is juf l useful nowadays to establish some special feature, but whether that special feature is worth the sacrifice is anpther matter. Breeders often wish to bring out some special feature in their stock, and by a few years of in-breeding and careful mating they establish that feature, und when once established it is not. necessarily lost bythe judicious employment of fresh blood. On the other hand, the special feature often becomes more prominent.

By a certain amount of in-breeding it is thus possible to improve certain points in our stock, but on the other hand it is more likely to bring out undesirable characteristics, such as want of bone and size, Bterility and delicacy of constitution. On the whole, therefore, in pedigree herds it is best to guard again H any system of in-breeding as far as possible, but in the breeding of commercial stock there can never be any justification for it whatever. The ideal of the pro ducer of good store stock should be to produce animals with size, quality, hair and constitution, that will live where others will starve, and that will turn the food given to them to the best account. This sort of stock will never be raised by a careless system of in-breeding, and so long as the sires used possess the characteristics which the breeder wishes to bring out in his stock, it matters little what their pedigrees are from a commercial point of view, so that they are unrelated, or very nearly so, to the previous sires used; and that brings up one little point, which is. the importance of breeders of commercial stock studying the pedigrees of the sires tfcey use otherwise they may inadvertently purchase a fresh sire which may be so closelv related to the previous on 9 as to do tsny infinite amount of harm if used too freely.—T.B.G., in Farmer and Stockbroker.

Experience has shewn that the full results of an experiment cannot always ba demonstrated within the period of a year, and that better and more definite results can be obtained if the experiments are continuous over a number of years. At the Ruakura State Farm fifteen acres of land have been divided into half-acre plots, each of which is to receive a dressing of manure and is then to be cropped. The treatment of manure is to be continued year after year; that is to say, a plot that received an initial dressing of basis s!ag will receive the same treatment throughout the period. To make quite certain of the experiments, duplicate plots will be cultivated in order that allowance may be made for any difference in the soils in various parts of the paddock, while no manure plots will also be cropped for purposes of comparison. Sweudes of one variety are being grown this year, while oats will probably be grown next year, without manure, in order that the condition of the soil may be tested.