There are different methods or techniques used for testing the performance of animals in livestock breeding and below are the techniques and processors used for testing performance in livestock breeding:
1) Progeny-Testing in Livestock Breeding
As the boar has a relatively large influence on the characteristics which the next generation of a pig herd will inherit, testing systems have tended to concentrate on improvement of boars.
Boar progeny-testing systems have been in operation throughout the world for a long time and are based on measuring the relative merit of a boar’s progeny from several sows.
This obviously gives a true indication of what a boar may be able to contribute towards the genetic improvement of a herd.
However, in addition to being very expensive progeny-testing takes a long time in order to accumulate the data required to evaluate a boar, which makes him relatively old before his potential is known. This reduces his useful life.
Consequently, as a routine system, progeny-testing has largely been superseded for traits of higher heritability by the performance test.
Nevertheless progeny-testing is usefully for assessing traits which do not lend themselves to performance-testing, e.g. sex-associated and slaughter traits.
2) Performance-Testing in Livestock Breeding
The basis of a performance test is that an animal own performance taken as a measure of its genetic merit and with traits of high heritability used as a guide to how its progeny will perform.
Thus the better individuals are selected from within group of contemporary animals that have been treated similarly.
The value and accuracy of a performance test can always be checked by running a subsequent progeny test seeing if the result agrees with the merit order of the performance test.
Performance test can be carried out at central performance-test station, where the environment standard for all animals tested. If facilities are adequate, testing can be carried out on-farm for within-herd comparisons.
Read Also: Intensive System of Livestock Production
The traits and selection criteria which are used in a test will obviously vary between countries according to their relative importance. They will also vary within that county depending on the use for which is used for generating gilts for commercial breeding, for example, will be different from those of a boar which is to be used as a terminal sire for the production of slaughter stock.
Nevertheless, various combinations of growth rate, feed-conversion efficiency and back-fat thickness are the traits which generally form the basis for selection.
Livestock Breeding Selection Methods
Selection methods also differ and the two mostly commonly used are: independent culling levels and the selection index.
1) Independent Culling Levels
In this method, a level of performance is set for each trait, and if a pig fails to reach the desired standard in any trait it is automatically culled. It can be likened to an examination system where if you fail any subject, you have failed the total examination.
A major weakness of this technique is that if a pig has outstanding qualities in some traits say growth rate and feed conversion efficiency. And just fails to reach the standard on conformation, it is culled.
The genes for the outstanding traits are therefore lost. This method is the main system used for judging merit in pedigree breeding schemes.
Read Also: Extensive System of Livestock Production
2) The Selection Index
In the index method, the traits to be selected for are combined for one animal into a total score or index. Each trait is normally weighted according to its economic value and heritability, so that the highest-index animal should yield the highest financial return. These economic weightings in the index can be adjusted as economic circumstances change.
The advantage of index method is that exceptional performance in one trait can balance out a weakness in another and if two traits are correlated so that improvement in one leads to a simultaneous decline in other required trait this can be allowed for in the weighting.
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