Research in Animal Breeding in Britain and U.S.A.
After representing New Zealand at the Review Conference of the Commonwealth Agricultural Bureaux, held in Britain last year, J. F. Filmer, Director of the Animal Research Division, Department of Agriculture, Wellington, spent a month visiting animal research institutions in the United Kingdom and a similar period in. North America. His impressions of the animal research work being undertaken in Britain and the U.S.A, and observations of the approach of those countries to problems of animal breeding were given in a paper which was delivered last month at the Ruakura Farmers’ Conference week and which is printed below. ANIMAL breeders in New Zealand have done a very good job. Probably no other country in the world has If million cows which would produce more butterfat under New Zealand conditions than our own cows produce. It is equally-doubtful if any other country has 20 million ewes which, under our conditions, would produce more money from wool and fat lambs than do our own flocks. But no thoughtful breeder would suggest that there is no room for improvement. The production of our best herds and flocks is well above the national average and within all herds and flocks there is considerable variation between the yields of individual animals. Moreover, it is doubtful if the average production per cow or per ewe is materially greater today than it was 10 years ago. How can the national average be raised to the level of our best herds and flocks? How can the flock and herd average be brought nearer to the level of the best ewes and cows within them? Those are the problems which we have to solve, and in New Zealand they are proving difficult problems. During my recent visit to Great Britain and America I therefore took every opportunity to learn how animal breeders in those countries were tackling these problems and what sort of results they were achieving. In Great Britain there is a very great revival of interest in animal breeding. A few years ago British breeders advertised widely that Great Britain was the stud farm of the world and that the quickest way to breed better stock was to import British sires; that idea is still very popular, but there is a growing realisation that even British stock can be improved. The Agricultural Research Council has recently purchased six properties which are to be used as new animal breeding research stations—two each for cattle, sheep, and pigs. In America, too, animal breeding is a very live subject.
Line Breeding and Hybrid Vigour In America any discussion on animal breeding leads almost immediately to the twin topics of line breeding and hybrid vigour. Outstanding success has been achieved in maize breeding by crossing inbred lines, and this has had a tremendous influence on nearly all animal breeding investigations. Line bred bulls, rams, boars, and cockerels, or sires resulting from crossing inbred lines, are already available. But little or no reliable information could be obtained about the relative production of their progeny. It is necessary to notice one very important difference between the programmes for breeding maize and animals. Hybrid maize seed results from crossing two parent lines each of which has been obtained by crossing two different inbred lines. The animal sire produced by crossing two unrelated line bred parents is mated to females which are usually not line bred. One of the most interesting investigations of line breeding is being conducted at the Sheep Experiment Station at Dubois, Idaho, U.S.A., where work is being done with the following three breeds of sheep: the Rambouillet, a plainbodied type of Merino; the Columbia, half Rambouillet and half Lincoln; and the Targee, three-quarters Rambouillet and one-quarter Lincoln. In each breed a number of lines have been developed and inbreeding has been practised within each line. The stage has now been reached where crossing of lines is starting. The presence of three breeds, the large number of lines, and now their division for crossing have reduced the ewes in each line to quite small numbers. Some very fine sheep have been bred; but it is not easy to determine how far line breeding has contributed. No progress has been made in increasing total wool production; percentage of yield of clean scoured wool and staple length are still rather low, while carcass size and conformation are good, and there is very little wool blindness, which used to be a problem. These sheep are being bred under difficult natural conditions. Three different areas are used for winter, spring, and summer grazing, and the sheep have to travel 200 miles every year. Break and tenderness in their wool, however, were not common. An annual ram sale is held on the property. No special feeding or fancy barbering is practised; in fact rams are sold a few weeks off the shears. Full particulars of weight of fleece shorn and clean scoured
yield for the ram and for the line from which he comes are made available to buyers. This was in marked contrast to the preparation given to some young Hampshire Down rams in England. They were grossly over-fat; their backs were shorn fiat with sharp edges, and their wool was dyed a brilliant orange.
At Edinburgh the Agricultural Research Council is embarking on an important line breeding project with Large White Yorkshire pigs. The buildings set a new high level in pig housing, the pens being constructed of concrete with hollow tile floors, double windows, and thermostatically controlled radiators. Accommodation is being provided for 120 sows and almost as many boars. In the first instance pigs will be purchased from any breeders who have practised line breeding. Each line will be inbred and at a later date the lines will be crossed and the boars from these crosses sold to commercial breeders. Careful records will be kept of the progeny of these boars to determine if they are superior to their half sisters by other boars.
Cross-breeding
Cross-breeding for meat is, of course, an old and well-established practice. At Beltsville in America experiments are being conducted on the crossing of different breeds of dairy cows. At this very large experimental station of the- United States Department of Agriculture cows are kept indoors, are fed standard rations, and are milked 3 times daily for 365 days per year.
Four breeds of cows are kept Jersey, Guernsey, Friesian, and Red Dane. Jersey, Friesian, and Red Dane proven' sires were available, and these were each, crossed with cows belonging to the other three breeds. Records are available for 54 2-year-old two breed cross heifers and these averaged 5851 b. of fat. Their purebred dams at the same age averaged 4421 b. of fat. Progeny of the same sires out of cows of their own breed did not show nearly such a spectacular improvement over their dams. A number of the two breed cows were mated to a bull of a third breed, and 2-year-old records are now available for 41 three breed crosses. These averaged 6061 b. of fat compared with a production of 6071 b. of fat by their two breed dams at the same age.
Reports of this experiment have met with a rather mixed reception in America. A similar experiment is. to be started by the Agricultural Research Council in Edinburgh. Jerseys, Friesians, and Ayr shires will be .' used, and in the foundation herd there will be 40 cows of each breed. To avoid any bias from a particular bull, semen, will be used from an artificial insemination centre on a random basis. Whatever semen is offering will be used on the . day a cow is mated, provided it comes from a bull of the right breed. Thirty per cent, of the cows in each breed will ways be mated with sires of their own breed. The remainder will be mated with sires of a different breed, and their two cross, progeny will'be mated with sires of a third breed. The results of this experiment will be awaited with great .interest.
. Another most interesting experiment at Beltsville is the crossing of Jersey cows with Red Scindi bulls. The Red Scindi is a milking strain of humped Indian cattle. Although its production is higher than that of most other Indian cattle, it has never approached that of good Jerseys. In the Beltsville experiment,- however, the crossbred cows produced at the same level as the Jerseys. This experiment needs to be repeated under tropical conditions, but it does suggest that this cross may prove useful in tropical countries if a reasonable standard of feeding can be provided.
At Compton in England a herd of Ayrshire cows have been mated to a Red Poll bull as a first step toward breeding a hornless strain of Ayrshires. Further steps will include top crossing with Ayrshire bulls and the use of selected crossbred bulls. In selecting the latter it is possible to exclude bulls which carry the factor for horns, as they, bear either small loose horns known as scurs or hard knobs under the skin at the horn site. In crossbred bulls which do not carry the factor for horns these are absent.
Theoretically it should be possible by the above methods to breed a herd of cattle which have all the characters of Ayrshires except their horns. At present the herd shows great variation, especially in- the shapes of the udders. If the experiment proves successful, there would appear to be no reason why the horns could not be bred off any breed of cattle by a similar cross.
Progeny Testing
In New Zealand during the last 10 years the attention of breeders, especially breeders of dairy cattle, has tended to be increasingly concentrated on progeny testing. In this system an attempt is made to locate bull's whose progeny are fetter producers than the progeny of the average bull. It is suggested that by the continued use of such bulls it will be possible to breed cattle which will breed true for high production. No attention is paid to the relationship between cows and the bulls to which they are mated. In other words an attempt is made to breed for production without line breeding. I think it may be fairly stated that both line breeding and progeny testing are still on trial, and it is well that they should be.
One of the obvious difficulties in applying the progeny testing method is the tremendous effect environment has on the progeny test of a bull. Let me give you a New Zealand example. At Ruakura we have used in the A.I. work two bulls with official sire surveys of 4511 b. and 3731 b. of butterfat respectively. The -bull with a sire survey of 4511 b. now has 118 artificially bred daughters in milk with an average production of 3481 b. of fat. (All figures are on a maturity basis.) The bull. with a sire survey, of 3731 b. has 28 artificially bred daughters in milk, and their average is 3461 b. of fat. It would appear that these bulls have almost exactly the same . inheritance for butterfat production, but there was 781 b. difference between their official sire surveys. One can only conclude that in the official surveys the progeny of one bull were better treated than those of the other.
Another New Zealand example: In an experiment at Ruakura extending over 3 years some identical twin, cows were fed concentrates at the rate of 21b. per gallon of . milk produced, and in addition were grazed on very good pasture. Thirty lactations from 18 cows averaged 4221 b. of butterfat. Very few bulls in New Zealand have a sire survey higher ' than 4221 b. But these cows had been selected as calvessimply because they were identical, twins. They were probably by k 8 different bulls of average quality.
Now an overseas example: In. Denmark 6 cows were selected in a commercial herd and it was decided tosee how much they could be made toproduce. They were housed under the best conditions; they were milked. 4 times daily by expert milkers; they each received the following astounding ration —6olb. of swedes, 91b. of hay, 91b. of silage, and 351 b. of concentrates. In the two seasons before the experiment they had produced. 3591 b. and 3701 b. of butterfat respectively. In the experimental season they produced an average of 9091 b. of butterfatnearly 2J times as much astheir previous best production. What, would you pay for a bull with a siresurvey of 9091 b. of butterfat?
These three examples show how very important the effect of environment can be in making a sire survey.. Discussions with overseas workers; indicated that they are conscious of this difficulty.
In Denmark progeny of bulls being, surveyed are brought together on special farms and are fed and milked under standard conditions. . Thisenables them to compare one bull with another, but it leads to disappointment, when the bulls are used on farms, where the conditions are not as good as those of the test farms.
. In Great Britain the Milk Marketing. Board is trying out a different system. Each year 5 yearling bulls will be used, at each A.I. centre. Semen from these bulls will be distributed to all farms, serviced in a purely random way. Theproduction of their progeny will later be measured on the farms on which, they are bred. Each bull will in this; way be represented by progeny on a. number of different farms, and theiraverage production should give somereal indication of his breeding merit. Over 100 yearling bulls are to be surveyed each year in this way. As it is possible that differences may exist between ■ the areas serviced by the various A.I. centres, the semen from one bull in each centre will be distributed to 4 surrounding centres as well as to the farms serviced from his own centre. This appears to be a well-thought-out plan, and the results, should prove very interesting. It is. hoped to initiate a similar plan at Ruakura using yearling sons of proven sires out of high-producing cows. Collaboration of dairy farmers in this, work is likely to be requested in thenear future.
The staff of the Herd Improvement Department of the New Zealand Dairy Board have, of course, always been very conscious of the great importance of environment. They first sought to assess its effect in individual sire surveys by making daughter-dam comparisons within the same herd in thesame year. Unfortunately only a relatively small number of such comparisons could be made, and they do not. always give a true assessment of the; sire’s real merit.
More recently the practice has been adopted of comparing the average pro-
duction of the sire’s daughters with the average production of all mature cows in the herd in the same season. The following table sets out the position in regard to the two bulls referred to earlier: —
In this case the daughter-dam comparison is flattering to bull A, but the comparison of daughters’ production with that of the mature cows in the same herds gives a very good assessment of the relative merits of the two bulls.
Progeny testing is still the best known method of assessing a bull’s real worth.
Every “merit bull” used at Ruakura has proved to be a good bull, though not always as good as his official sire survey suggested. It is still wise to buy a “merit bull” if one can be found. But if you want to know what he will do in your herd, inquire very carefully about the conditions under which he was surveyed, and note how they compare with yours. Remember those ordinary cows in Denmark which produced 9091 b. of butterfat!
What has been said might perhaps appear to indicate that feeding is more important than breeding. The truth is that breeding is always important. Experiments with identical twins and with artificial insemination at Ruakura have shown that well-bred cows produce more than poorly bred cows even when both are poorly fed.
Selection on Performance
Perhaps the oldest idea in breeding is that like begets like. Even when breeding for performance it sometimes works quite well; for example, if you want to breed a fast horse, use a thoroughbred sire. His progeny may not gallop as fast as you would wish, but they will be much faster than the progeny of a draught stallion.
An interesting example of this method of breeding was seen at Miles City in Montana, U.S.A. Here an experimental station is investigating the breeding of Hereford cattle. It was found that there was a considerable difference in the rate at which different bulls grew during their first 2 years. Further investigations showed that the progeny of the bulls grew at approximately the same rate as their sires. By selecting for rapidity of growth the station has evolved a type of Hereford which, under quite hard range conditions, reaches forward store condition at 2 years of age, and requires only 2 to 3 months’ grain feeding to kill at 550 to 6001 b.
One very important finding is the fact that the rate of growth does not affect the appearance of the bulls at maturity. A rapidly maturing bull cannot be picked on his looks. It seems possible that this principle can he applied to fat-lamb breeding. If .some Southdown rams grow faster than others, they may pass this character on to their offspring. It is intended to have a look at this question at Ruakura.
Fundamental Experiments in Breeding “. , - Experiments to determine the fundamental principles of genetics are not often conducted with domesticated animals, because they would be too
slow and too expensive. A truly fundamental experiment has, however, been planned by the Agricultural Research Council in Scotland, using Scottish Blackface sheep. A large estate has been bought in the Highlands, and it is intended to run 3 groups each of 1000 ewes in exactly the same environment. In the first group no selection will be practised and sufficient ram lambs will be reared within the flock each year to mate with the ewes. Any variation in the wool production of the ewes will thus depend entirely on variations in their environment. In the second group an attempt will be made to increase the wool production, and in the third group an attempt will be made to decrease the wool production. This is a very important experiment. If real differences in wool production are produced, it will be possible to say that they are really due to the breeding methods used. Only too often animal breeders have attributed improvements to breeding which were really due to improved environment. Because of the cost and the slowness of fundamental breeding experiments with domesticated animals, some preliminary experiments are being conducted with mice at Edinburgh. One experiment will serve as an example. 'lt is strongly held by some animal breeders that to pick the best animals to breed from they must be given the very best environment. An experiment was conducted with mice to test this theory. An inbred line of mice was divided into two similar groups, one of which was fed on a ration above normal level and the other on a ration below normal level. Efforts were then made to breed bigger mice and after a number of generations the size was increased in both groups. They were then placed on the same intermediate level of nutrition and it was found that the mice bred on the low plane of nutrition were actually bigger than those bred on the high plane. This should, of course, not be used as an argument for under-feeding, but it does show that over-feeding of stud stock is not necessary. In another experiment the methods of inheritance of milk secretion were studied in mice. The following paragraph is quoted from the introduction to the paper describing the results: —* Mice, with their rapid and prolific breeding, possess many advantages for the experimental study of lactation, and allow genetical experiments to be made on a scale that would be impracticable with cattle. The logical analogy between mice . and cows would, of course, require • justification, and knowledge about lactation in mice could not be applied indiscriminately to the improvement of the milk production of cows. Nevertheless, if a plan for the improvement of milk production had been tried on mice and had failed, much faith and courage would be needed to put it into
' . •Vl operation on a herd of dairy cattle. Experiments on the lactation of mica might, therefore, be of considerable prognostic value to the dairy-cattle breeder, and also supply more fundamental knowledge of lactation in general. It does seem that mice might be used in. New Zealand for some preliminary experiments in this way. ■ Mechanics of Reproduction Brief reference may be made to some extremely interesting investigations at Cambridge into the mechanics of reproduction. It is well known how, by A. 1., the number of descendants of an outstanding bull can be greatly increased. It is now suggested that outstanding cows can also have the number of their progeny multiplied. By injecting hormones into the cow she can be persuaded to produce many eggs instead of one or two at each heat period. These can all be fertilised with semen from a proven sire, and a method has been devised for collecting the fertilised eggs from the uterus. Each of these is then placed in the uterus of another cow—any sort of cowwhich has just passed a heat period. In this way it would be possible to produce in one year 100 calves, all sons and daughters of one outstanding cow and one proven sire. Rabbits, sheep, and goats have been successfully bred from transferred fertilised eggs. There is thus nothing fantastic in the idea. So far, however, no calf has been born alive from a transferred fertilised egg, though on several occasions development has proceeded in the foster mother for several months. It may be that some day we shall import from England a dozen fertilised eggs from a champion cow at about the same price as a dozen fertilised hen eggs! Whether or not this vision ever materialises, it is certain that much valuable information will come from the investigation. Let me give two examples. It has been shown that when a fertile bull is used almost 100 per cent, of his matings result in fertilised eggs; 100 per cent, of calves do not result, because a considerable percentage of the eggs die within a few weeks of fertilisation. This has directed the investigation of sterility to a new avenue of research which may well prove to be very fruitful. The experiments aimed at producing many eggs at each heat period have shown that the number of young which result may be controlled by the dose of hormone and the time at which it is injected. It is suggested that if a “teaser” .ram is run with ewes, and a carefully measured dose of hormone injected 12 days after the ewes are marked by the teaser, 2 to 3 lambs will result from mating with a fertile ram at the next heat period. This practice should be quite feasible for fat-lamb breeders, and, if successful, should prove very profitable. It is to be tried at Ruakura next season. I trust that enough has been said to show that a great deal of very active research in animal breeding is going on in both Great Britain and America. There are not many new discoveries which can be applied immediately in New Zealand. There are, however, a number of ideas which appear to be worth incubating, for nothing more fertile than an idea has ever been conceived.
* D. S. Falconer (1947), J. Agric. Sci., 37, 3, 224.
Official surveys Artificial insemination Bull Daughters Dams Mature cows Daughters Mature cows Av. b/fat lb. Av. b/fat lb. Av. b/fat lb. Av. b/fat lb. Av. b/fat lb. A .. 451 367 430 348 319 B .. 373 346 360 346 322
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Bibliographic details
New Zealand Journal of Agriculture, Volume 82, Issue 6, 15 June 1951, Page 477
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4,009Research in Animal Breeding in Britain and U.S.A. New Zealand Journal of Agriculture, Volume 82, Issue 6, 15 June 1951, Page 477
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