ANIMAL BREEDING
By FRANK SYKES
OVER the past twenty-five years great advances have been made in the theory and practice of feeding farm animals. Years ago stock were fed by rule of thumb. For instance, great weights of mangolds were fed to much cows without the realisation that it was the water contained in the roots, rather than their feeding-value, which allowed cows to milk well when stall-fed and with only occasional access to drinking water. The right food for a fattening pig was considered to be barley meal, regardless of the fact that barley contains insufficient protein for maximum growth. Nowadays water is laid on to cowsheds, and the farmer aims at a balanced ration containing the right proportion of carbohydrates and proteins. Advance on these lines will continue, but the pace of the advance will decline as the principles of scientific nutrition come to be adopted by farmers in general.
As one line of advance shows less promise a new vista reveals itself in the application of the science of genetics to farm animals. By such means the productivity of our farm stock may be increased by fifty per cent, within the next twenty years. Plant-breeders have already made great use of this comparatively new science. Plants are relatively simple organisms, and Mendel with his experiments in breeding smooth and wrinkled peas made the early discoveries from vegetable life. Now we know sufficient to apply genetics to the breeding of farm stock. I was brought up to believe that where breeding was concerned "like produced like." If that were com- pletely true there could have been no improvement in our farm stock over the past hundred years except as a result of improved feeding. Selective breeding—breeding from the best—combined with im- proved feeding, has raised the standard, but we are arriving at a point beyond which selection and good feeding cannot take us much further. Any advance is small, and the tendency to slip back becomes more pronounced.
The truth of the matter is that like produces like occasionally, but only occasionally, where selective breeding is practised. In every parent there are factors which may be hidden for several genera- tions, but which have a disconcerting habit of bobbing up. I can best illustrate my meaning by recounting the breeding history of a famous world-record cow. Bought in a bunch of Irish-bred Shorthorn heifers of undistinguished breeding, this cow was milked in a large bail herd for several seasons until an observant dairy- manager picked her as an exceptional milker. Given every chance she produced 4,000 gallons of milk within a single year. Mated to a first-class Shorthorn pedigree bull, she produced some useful heifers, but nothing as good as herself. Her daughters were mated- in their turn to pedigree Shorthorn bulls, and to the surprise of everyone two bull calves were born showing every characteristic of Hereford cattle. There can be no doubt that the original record- breaking cow had Hereford blood in her. As a milk-producer she was exceptional, but as a breeder she was a failure. Hereford cattle are not generally heavy milkers, but by some million-to-one chance of the arrangement of the genes of her make-up this cow had the capacity and the constitution to create a world record. This arrange- ment had much the same chance of being repeated in her progeny, so that her selection as a breeder was doomed to failure.
The aim of the commercial breeder of animals is to produce stock which are economical converters of animal-food into human food. Of recent years our pedigree-breeders have tended to aim at the beautiful animal. Agricultural shows have encouraged this tendency, and where beef animals are concerned no great harm has followed. An Aberdeen Angus bull which itself would make a good carcase of beef is quite likely to sire good beef' progeny, but a Dairy Shorthorn bull which could not be faulted in the show-ring is as likely as not to throw a proportion of daughters which are poor milkers even if mated to the best bulls. In farming it is the average that counts. One or two outstanding animals in a herd will not make up for others which are uneconomical to keep. Even where meat-producing animals are concerned it is impossible to judge in the show-ring whether they are economical converters of food. All that is patent to the judge is that, given the best of food and attention, they are capable of producing top-quality meat. Show beef animals are often fed far more milk than their dams can produce, and no count is taken of the cost of feeding them. Dairy cows can be judged on the quantity and quality of milk they give or have given, but here again there can be no indication as to whether they will pass on to thefr daughters their own capacity to yield milk. Because cows lose their good looks with age, few old cows are seen in a show-ring, so that there is seldom any indication that, show cows have the constitution to reach old age and to resist disease.
The ideal for the milch cow will vary according to climate and conditions. It would be useless for a Highland crofter to keep a potential thousand-galloner if sucka cow had to forage for a living on the hills. In this case a cow with the ability to fend for itself would be of more value, even though it gave less milk. For the average herd in a dairying district the farmer wants a cow capable of producing a thousand gallons per annum with ordinary feeding and attention, capable of living for nine years or more, and capable of producing heifer calves which will be as good as their dam when their turn comes to run with the herd. At present a small propor- tion of the cows in most herds reach this standard, except that they do not produce their like. Where the breeding factor is concerned there is great uncertainty. Good cows are bred from poor dams and vice versa, with a result that the average production is about half the ideal I have mentioned, and the average life in the dairy is little more than two years.
How are we to improve? The first step must be by the use of proven sires. These are animals which have been found by experi- ment to raise the performance of their daughters over and above that of the dams. This is not so easy as it seems. Where cattle are concerned a bull is five years old or more before his daughters have milked through their first lactation and before they give a cettain indication of the value of their sire. Before that time dairy bulls are apt to be fierce and a nuisance. Even then a proven bull has half its useful life in front of it, and by the use of artificial insemination the number of its progeny can be much increased. All this is but following the lead of the racehorse-breeder. The value of a stallion on the turf depends to some extent on his breeding, to some extent on the races he won when in training, but to a greater extent on his success as a sire of racehorses. Well-bred mares that have never won races themselves have a value. If they breed winners their value rises proportionately. Many brilliant fillies never breed good progeny, whilst some mares undistinguished before they went to stud have bred famous racehorses and stallions whose names embellish the best pedigrees.
The use of proven sires in only a start in the right direction. The original Shorthorn cattle and improved Leicester sheep which were the precursors of our modern breeds were both achieved by close inbreeding. That was the way that characteristics were stamped into those breeds. Inbreeding is a dangerous weapon except in the hands of the expert, but by scientific inbreeding it will be possible to stamp good qualities into animal families.
Most of the maize Aown in The U.S.A. in these days is produced from seed which has been crossed from two inbred &trains. Neither of these strains produced by the plant-breeder is exceptionally pro- ductive, but if the two are grown together and the cobs of one line and the male tassels of the other are removed, the cross-bred seed produces a plant which is twenty per cent, more productive than the best pure-bred strains in use previously. Mr. Henry Wallace arrived in this country clutching a box of eggs. In certain circles he is more famous for his poultry than his politics. He has produced lines of inbred hens which are crossed for commercial purposes. The result- ing chickens, from what the geneticist terms homozygous parents, are not exceptionally heavy layers, but each chicken will reach a high standard, and the overall average production of a flock bred in this manner will be higher because the genetic make-up of each is for practical purposes the sarne, and good.
In Minnesota they have produced by inbreeding for a number of generations a line of pigs which will not only give good bacon but which will give a pound of meat for half the food that the average pig requires. Denmark and Holland are making great progress in the breeding of dairy cows on progressive lines, and we are losing our former pre-eminence as the stud of the world. The Royal Agricultural Society played a great part in the encouragement of animal-breeding a hundred years ago. There is now an opportunity for the society to take the lead again. Much of our best breeding stock will not be represented at the " Royal " at Lincoln because all the best stock from a breeding point of view does not conform to present show standards. It is time for the governors of the society and for. breed societies to ask themselves whether their standards are not out of date.
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