DAIRY FARMERS.

Franklin Times, Volume 9, Issue 727, 2 May 1922, Page 2

DAIRY FARMERS.

LINE BREEDING. In connection with thel Inglewood Jersey Cattle Club a paper was r.ead jyt a recent meeting, contributed by My W'. H. Booth, of Carterton. Mr Booth’s paper was both interesting and instructive, and is therefore well wonth attention : I may say that fifteen years o.r so of line breeding Jersey cattle is not sufficient time to get enough experience to write or speak wi|th .authority on the subject of breeding, but I can give the members some concise idea of the way that I am endeavouring to improve my own herd by not going too far, away from the old parent stock- I cannot claim much originality in Ithis paper; for years past breeders have studied the many ways, by coss-breeding, line and in-breeding, to improve their stock. Without doubt in-breeding has been used in the improvement of all our domestic breeds, though now there may not be the necessity as in the past. And from this sysem of in-breeding certain modifications have Arisen. Possibily Darwin’s theory that in-bi ceding had a tendency to produce infertility and lack of constitution made breeders chary oi going too deeply in this di ection. Although this theory is often doubted, sti.fl, line-breeding is more often advocated and used in a number o;fp rogressive herds as being safe in the long' run. Taicen as a general rule any animal that has over 50 per cent, of a particular blood may be considered in-bred in that s'V’ain —SO per cent, and under should constitute a line-bred animal. A veteran Scotch Sho'ttborn breeder wrote this following paagaph “Straight breeding with a limited range of pedigree— striving steadily to improve the stock descended from the foundatipn herd—making deeper rather than wider the life streamchecking instead of introducing the tendency towards variation —gaining hereditary power by intensifying a few instead of combining many lines.”

This is an explanation of line bl eeding. Top ult it another way, itis continually breeding from and along the lines of a particular family. Here the tendency of the strain would seem >*co .run over the 50 per cent, in few weeks, but in the, past our crosses have been used so that in my own case I find that 12,.25 per cent, is about the maximum that I can keep in my breeding.

To explain the system of line breedins move definitely and taking- my own experience I would recommend anyone starting in a small way to purchase one good cow with as few faults as possible, but if he desi.es m«;e let him buy ones of the same family breeding. Having secured the foundation stock there comes the question of sire. If the foundation stock is satisfactory go to the foundation herd for the- sire, using cue of the same family fchat measures up closely to the standard of the breed, then breed from that side and go back to the foundation herd for a second one of somewhat similar blood, even using one of his own breeding when satisfied that his own system is producing as good and better female as the original stock. But if the foundation stock does not produce a sire up to the best standard, then necessity gives us an option of two things, either to look around the country. and see if a superior sire cannot be got of scmewha't similar breeding to our own stock. This climatic out-."Voss should suit any breeder who may be chary of too

close breeding, and it would follow what the dissimiW ity 'of climatic and feeding should put a little e:;bra amount of constitution on the she .f he conditions und*r which they arc b ltd are mote severe. Or if the best si e can only be got from an outside herd bred on dillerent lines, then of necessity use him, as nvv experience does not gj.ve me sufficient knowledge to advocate using ns si o on bis own stock. 1 would • ecr arm end that the breed*.- go back •md procure another 1 sire from ; the same best herd and so go on, using similar sires until the time comes when the good points of the other herdi .< e incorporated in his own : then he may consider the possib'.l-ity of occasionally using a sire of his own breeding.

It would be difficult in the above two cases to advise a breeder what percentage of inferiority can he allowed between a sire of 'the original! foundation stock as against a perfect ig: , but some points could be allowed in favour of the fo.mer. Of course the breeder mus’t understand that constitution is the first aim in all breeding ope aliens, and by gutling owes and sometimes a cow of simffnn” breeding lines f/om a disti nrc bur made me believe that this climatic out-c-rosr is one of the best

of line breeding*. If the breeder is doubtful of too close line breeding there ;fe two other methods of line breeding, but the blood is not so accentuated, but gains may be made in improvement in type. The one way is to introduce a superior cow into the herd and by crossing with your own bred sire [reducing a sire or daughter that can be used or bred from, again and so carry on the original system. The first outside cross may bring the blood lines down 50 per cent., but the second and future crosses increase the proportion of the old blood'. In the same way the best cow or heifer may be sent out to bleed and their progeny used to carry on. There is the one weakness in line breeding—that you perpetuate faults as well as good qualities 1 . Good methods of selection a e then necessary to improve or cut out the inferior qualities. One can be confident that the good points (and there should be many to start with) are handed down, and though there may be something inferior, yet the chances are great that the next generation *rorn this inferior animal will return to the average of the h m d. I have nod ced that a bull that has shown weakness in the progeny in another herd of mixed lines has when crossed with a strain of similar blood lines shown excellent results And as to weak points, in all breeding the intelligence of the breeder must play a g eat p-nt in correction. So he must decide for himself how far he can pile up the good points at the expense of a few w'ak ones.