Publications by authors named "Averdunk G"

Genome scans for quantitative trait loci (QTL) in farm animals have concentrated on primary production and health traits, and information on QTL for other important traits is rare. We performed a whole genome scan in a granddaughter design to detect QTL affecting body conformation and behavior in dairy cattle. The analysis included 16 paternal half-sib families of the Holstein breed with 872 sons and 264 genetic markers.

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A joint analysis of five paternal half-sib Holstein families that were part of two different granddaughter designs (ADR- or Inra-design) was carried out for five milk production traits and somatic cell score in order to conduct a QTL confirmation study and to increase the experimental power. Data were exchanged in a coded and standardised form. The combined data set (JOINT-design) consisted of on average 231 sires per grandsire.

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A whole-genome scan to detect quantitative trait loci (QTL) for functional traits was performed in the German Holstein cattle population. For this purpose, 263 genetic markers across all autosomes and the pseudoautosomal region of the sex chromosomes were genotyped in 16 granddaughter-design families with 872 sons. The traits investigated were deregressed breedingvalues for maternal and direct effects on dystocia (DYSm, DYSd) and stillbirth (STIm, STId) as well as maternal and paternal effects on nonreturn rates of 90 d (NR90m, NR90p).

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Genes determining the bovine erythrocyte antigens were mapped by linkage analysis. In total 9591 genotypes of 20 grandsire families with 1074 sires from a grand-daughter design were elucidated for the genes determining the erythrocyte antigens EAA, EAB, EAC, EAF, EAJ, EAL, EAM, EAN', EAR', EAS, EAT', and EAZ according to standard paternity testing procedures in the blood typing laboratories. Linkage analyses were performed with 248 microsatellite markers, eight SSCP markers and four polymorphic proteins and enzymes covering the 29 autosomes and the pseudoautosomal region of the sex chromosomes.

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Twenty paternal half-sib families of a granddaughter design were genotyped for 265 genetic markers, most of them microsatellites. These were 16 Holstein families, 3 Simmental families, and 1 Brown Swiss family. The number of sires per breed was 872, 170, and 32, respectively.

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The proportion of unpigmented coat on the trunk was determined from photographs of 38 German Simmental and 627 German Holstein bulls distributed over three generations. All 665 animals were members of 18 Holstein and 3 Simmental half-sib families. A Bayesian estimation of heritability yielded a posterior mean of 0.

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In the time between 1989 and 1991 seven Brown Swiss heifers, which had clinical signs of the Weaver syndrome were kept at the Bavarian Institute of Animal Breeding in Grub. This was in order to investigate this hereditary trait further. The number of animals carrying this genetic defect was increased by means of embryo transfer.

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