Progeny Testing

It is obvious that the only sound and reliable test of thebreeding worth of an animal is the quality of its offspring.No matter how good a show specimen a rabbit may be, or hownearly perfect a pelt it has, unless it can reproduce thesecharacteristics in its progeny, it is of little value as a breedinganimal. Performance testing implies the measurement of theefficiency with which a rabbit, or a group of rabbits, producesmeat, pelts, young stock etc. Progeny testing implies theestimation of the breeding value of an animal by the perform-ance of its progeny.

In the breeding of rabbits solely for exhibition purposes, thecriterion of the breeding value of a rabbit differs from thecriterion to be used in the economic production of, say, meatrabbits. In the latter case a breeder will want to produce auniform set of good quality meat rabbits, whilst the exhibitorwill scant to produce several outstanding animals. It does notreally matter to the exhibition breeder whether the stock heproduces are variable, so long as he produces one or two reallygood animals. As the breeding of show specimens can neverbe an exact science, but rather more of an art, performance andprogeny testing cannot be used to such advantage as it can inthe production of utility' rabbits.

Economic production of rabbits for meat and fir depends on large litter size, good and cheap growth, and freedom fromexcessive mortality. Certain does will be found to have alarger than average litter size, and to do their young so wellthat their growth rate is high. Clearly progeny from suchdoes will be selected for future breeding stock.
If the records of the progeny of a group of does, mated todifferent bucks, are examined, it will be found that the averageof the different groups sired by the different bucks, will vary.One buck may consistently produce progeny which haveperhaps a better carcase and a better growth rate. Clearlyagain, the progeny of this buck should be selected for futurebreeding rather than the offspring of another buck, theaverage quality of whose youngsters was not so good.

The most important factor to be recognised in any progenytest is that the progeny should be unselected for the character-istics considered. That is to say it is of little value to pick outsay the six best animals sired by one buck for comparison withthe six best sired by another. Ideally, all the young sired byall the bucks should be compared, but when this is not possible,the animals to be compared should be picked quite at random.
Since, also, the qualities of an animal are made up from bothits genetic constitution and the effects of its environment,comparisons should be made of the progeny of different bucksreared under exactly the same conditions.

With progeny testing it is essential that the qualities orcharacteristics which are measured and compared should bedue to heredity to as great an extent as possible. To recordthat the progeny of a buck have inferior growth rates dueto their inheritance when in fact the cause is due to faultyfeeding or to disease, immediately makes the test useless.

There are unfortunately, some difficulties in the way ofcomplete progeny testing. To begin with, accurate recordingis absolutely essential, and although it is of great advantageto all breeders to keep full sets of records, few do so. Secondly,the number of progeny which must be kept until the test isconcluded is usually rather larger than is maintained in theaverage stud. As culling cannot be practised until the test iscomplete there is also a certain amount of expense.

Nevertheless, by the recognition of the fact that the breeding value of an animal lies in the quality of its progeny, the breederwill be encouraged to select his breeding stock on a morerational basis than simply by its external appearance.