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Need for sharp phenotypes in QTL detection for calving traits in German dairy cattle
Project
Project code: DFG 27542638
Contract period: 01.01.2006
- 31.12.2010
Purpose of research: Basic research
The aim of the study was to investigate whether parity-specific phenotypes provide a clearer
picture of QTL affecting calving traits in German Holsteins than breeding values estimated
across parities. In experiment I, approximate daughter yield deviations were calculated by
applying a univariate sire model assuming unrelated sires used as phenotypes in a QTL
mapping study. These results were compared to those obtained using deregressed estimated
breeding values obtained from the routine German sire evaluation (experiment II). In
experiment I, 17 chromosome-wise significant QTL were found for the first parity, but only
12 for the second parity. Only three QTL for maternal stillbirth, located on BTA7, 15 and 23,
showed an experiment-wise significance. Experiment II revealed 15 chromosome-wise
significant QTL. The results differed markedly between first and second parity within
experiment I, as well as between experiment I and II. The present study showed that parityspecific
daughter yield deviations are beneficial for mapping QTL for calving traits.
Furthermore, it is expected that the use of sharper phenotypes will also be advantageous for
QTL fine mapping and the identification of candidate genes.
Section overview
Subjects
- Animal breeding
- Animal health