Genet. Sel. Evol.
Volume 40, Number 2, March-April 2008
|Page(s)||195 - 214|
|Published online||27 February 2008|
Quantitative trait loci for fertility traits in Finnish Ayrshire cattleNina F. Schulman1, Goutam Sahana2, Mogens S. Lund2, Sirja M. Viitala1 and Johanna H. Vilkki1
1 MTT Agrifood Research Finland, Biotechnology and Food Research, 31600 Jokioinen, Finland
2 Department of Genetics and Biotechnology, Faculty of Agricultural Science, Aarhus University, Research Centre Foulum, 8830 Tjele, Denmark
(Received 17 May 2007; accepted 25 September 2007; published online 27 February 2008)
Abstract - A whole genome scan was carried out to detect quantitative trait loci (QTL) for fertility traits in Finnish Ayrshire cattle. The mapping population consisted of 12 bulls and 493 sons. Estimated breeding values for days open, fertility treatments, maternal calf mortality and paternal non-return rate were used as phenotypic data. In a granddaughter design, 171 markers were typed on all 29 bovine autosomes. Associations between markers and traits were analysed by multiple marker regression. Multi-trait analyses were carried out with a variance component based approach for the chromosomes and trait combinations, which were observed significant in the regression method. Twenty-two chromosome-wise significant QTL were detected. Several of the detected QTL areas were overlapping with milk production QTL previously identified in the same population. Multi-trait QTL analyses were carried out to test if these effects were due to a pleiotropic QTL affecting fertility and milk yield traits or to linked QTL causing the effects. This distinction could only be made with confidence on BTA1 where a QTL affecting milk yield is linked to a pleiotropic QTL affecting days open and fertility treatments.
Key words: QTL / fertility / dairy cow
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