Association Between Milk and Blood Polymorphism Types and Lactation Traits of Holstein Cattle

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Abstract
Relationships between polymorphism type at 9 genetic loci and 1st lactation production of Holstein cows were investigated. The total data included 3107 lactations, which represented 18 years, 126 sires and 8 herds. The analyses include adjustments for herd, sire, year and season effects. Significant milk and fat yield differences were indicated for the F blood group system. Constant estimates for the FF/FF, fF/fV and fV/fV genotypic classes were -80, -191 and 271 kg milk and -4.3, -9.0 and 13.1 13.3 kg fat, respectively. Milk and fat yield differences were significantly associated with the 5 genotypic classes involved at the transferrin locus. Constant estimates for the TfA/TfAL TfA/TfD, TfA/TfE, XfD/TfD and TfD/TfE cows were 348, 158, -56, -42 and -409 kg milk and 13.8, 5.5, -5.1, 1.7 and -16.0 kg fat, respectively. Alleles at the B blood group locus were significantly associated with fat percentage differences. There was some evidence of association between S locus alleles and fat yield differences. In general, the A, J, K and Z loci appeared to have no noticeable effects on the 3 production traits. Analysis of a smaller number of animals (669) failed to indicate any relationship between [beta]-lactoglobulin type and the production traits.