for the presence of chromosomal de-fects such as transloca- tions. The cheapest method is karyotyping, which costs mini- mal € 65/animal. However, it is also a relatively inaccurate test, and it may incorrectly show a chromosomal defect or fail to detect actual defects. It is, therefore, risky to use only kary- otyping as the criteria for the final approval of an AI boar. The alternative method (FISH test) is by far more accu-rate but also more expensive, costing at least € 270/animal. For eco- nomic reasons alone, this is therefore not a feasible solution in a commercial breeding programme with thousands of potential AI boars annually. Most importantly, both tests incorporate the risk of culling top breeding boars with no problematic translocations – and thereby risk losing genetic progress. Instead, the DPRC has developed a data-based model that protects the breeding programme from any chromosomal defects that have detrimental effects on fertility.
Progress driven by data To protect the breeding programme from any detrimental chromosomal defects, a data-based model was developed
and integrated in the selection for the trait “male fertility” in DanBred Duroc in 2015 and for the trait LP5 (live piglets on day 5 after farrowing) in DanBred Landrace and DanBred Yorkshire in 2016. In order to identify boars or sows with a translocation detri- mental to fertility, the DPRC investi-gates their estimated breeding values for the traits male fertility and LP5. If the breeding value is substantially lower than expected, i.e. low- er than what might be caused by random fluctuations, then this is a clear indication of chromosomal defects being the cause. Consequently, the animal will no longer be useful as the breeding nucleus, and its offspring will not be good se-lection candidates for the next generation. This way, it is possible to prevent chromosomal defects in AI boars that would have otherwise been detrimental to reproduction re- sults in production herds. Moreover, it is also possible to pre- vent the passing on of detrimental chromosomal defects to future generations. This data-based model ensures that breeding is continued with only the best selection candidates in the breeding programme to achieve the highest possible genetic progress.
▶PIG PROGRESS | Volume 36, No. 1, 2020
Result of a good translocation: a sow with a large litter.
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