Bull testing, CVM
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| Bull testing, CVM |
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The objective of the test mating is the early and reliable evaluation of breeding bulls according to the performance and other economically important characteristics and traits of their progeny; it constitutes the basis for the estimation of breeding values and the selection of the best bulls for their utilization in artificial insemination.
1. Testing basis and progeny testing herds
1.1. The progeny testing herd consists of Holstein herds registered in the Herd Book and other performance recorded herds using artificial insemination.
1.2. The optimum proportion of insemination with semen of tested bulls within both the active population and individual herds is 20-30 % of the total number of inseminations with semen of Holstein bulls.
1.3. The main testing procedure is based on the insemination of all first parity cows (completed with the insemination of unselected second parity cows if necessary) continually throughout the year. Only exceptionally and as a supplementary routine the time limited testing of all cows in the herd without their preliminary selection on performance, reproduction cycle, type, and other characteristics can be used. Involving heifers in the test mating is not recommended mainly due to the increased risk of the frequency of calving difficulty.
1.4. Only the cows with the minimum proportion of 75 % of the Holstein breed are used in the test mating.
2. Test mating organization
2.1. The test mating is organized by the owners of breeding bulls or their semen; the commencement of testing is announced to the Czech-Moravian Association of Breeders.
2.2. Only the bulls until the age of 24 months registered in the Herd Book are involved in the test programme.
2.3. For testing purposes, i.e. from the beginning to the end of the testing period, at least 800 inseminations are carried out; however, with regard to achieve the required reliability of breeding values for economically important traits with low heritability, it is recommended to perform such a number of inseminations to obtain 120 to 150 daughters from a tested bull.
2.4. The optimum testing period is 2 to 3 months; it should not exceed 6 months. The commencement of testing is registered after at least 10 inseminations with semen of a given bull had been carried out. Unless the owner of the bull announces a temporary interruption of the test due to serious reasons (e.g. disease of the bull), the test is terminated once the number of inseminations in a current month decreased below 20.
2.5. It is important to use each tested bull in at least 30 herds of at least 20 different agricultural enterprises with varied production levels.
2.6. The extent of use of bulls among different herds has to be balanced and has to correspond to the respective herd’s size; it should not exceed 30 inseminations in a herd. With the exception of small size herds, at least 3 different test bulls should be simultaneously used in a herd.
2.7. To achieve a higher reliability of results, it is recommended to use a part of AI units of tested bulls in a herd simultaneously with the tested bulls of other owners.
2.8. After the termination of the test it is recommended not to use the bull or to restrict markedly its use for the period of at least 6 months.
3. Systems of testing
3.1. The main testing system is based on the organized test mating of young bulls from AI stations in the Czech Republic which participate in the implementation of the breeding programme within the entire population.
3.2. International testing, i.e. the evaluation of bulls owned by foreign companies, is used as a supplementary system. The most appropriate method is the simultaneous testing (joint and coincident test of a bull in the CR and abroad) but different methods are not excluded. In case the international testing limits the testing of bulls from national owners, the Committee of the Association has the authority to regulate its extent through the measures declared in the Commission Decision No 96/509/ES of June 18, 1996.
4. Evaluation and application of test results
4.1. The test mating system is registered and supervised by the Czech-Moravian Association of Breeders. The main subjects of supervision are the number of performed inseminations and conceived cows, length of the test period, and other rules valid for the testing system.
4.2. The Czech-Moravian Association of Breeders together with the Herd Book Board also checks the validity of the data used to calculate breeding values and is responsible for the timely and complete publication of results.
5. Final provisions
5.1. The owner of the bull or semen informs the designated organization (Czech-Moravian Association of Breeders) in writing and in due time about the inclusion of the bull in the testing programme.5.2. The test can be commenced only after the registration of the bull in the Herd Book. The application for registration of the bull in the Herd Book comprises the information that the bull (or its semen) will be involved in the test programme.
5.3. These rules are part of the Holstein breeding programme approved by the Ministry of Agriculture of the CR.