Submitted to: Plant and Animal Genome VX Conference Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: January 17, 1999
Publication Date: N/A
Preliminary analysis of quantitative trait loci (QTL) that affect milk yield, health, and conformation traits in seven large U.S. Holstein grandsire families has been completed. Predicted transmitting abilities, standardized transmitting abilities, and daughter deviations were analyzed for association with marker genotypes using analysis of variance. Strong evidence (P = 1.11x10-7) was found for a QTL associated with marker BMS470 on chromosome (BTA6) for protein percent in a single grandsire family. A total of 74 sons have been genotyped from the Dairy Bull DNA Repository. Eleven additional informative microsatellite markers from the USDA Meat Animal Research Center BTA6 linkage group covering a region from 51.9 to 91.9 cM were genotyped for animals in this family. Interval analyses using a simple regression method provided strong support of a QTL located 52-57 cM from the centromere on BTA6. Permutation test results provide additional evidence of a segregating QTL in this family (P < 10-5). Evidence for an effect on fat percentage was also identified in the same region (P = 0.009). Only marginal support exists for a QTL affecting milk yield in the same region (P = 0.029), while no evidence was found for effects for fat or protein yields on the region of BTA6 investigated (P = 0.519 and P = 0.561). Development and analysis of additional informative markers centromeric to BMS690 is underway to bracket the location of the putative QTL in this family.