Submitted to: Plant and Animal Genome VX Conference Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: December 1, 1997
Publication Date: N/A
Technical Abstract: Quantitative trait loci (QTL) affecting economically important traits, such as milk production, health, and type, are currently being identified in dairy cattle. Some of these QTL will be exploited in marker-assisted selection in which flanking genetic marker genotypes will be used to predict an animal's potential prior to progeny testing. The objective of this study was to identify QTL for milk production, health, and type in seven large Holstein grandsire families using the granddaughter design. The families were genotyped at twenty microsatellite markers located on fifteen chromosomes. Marker allele effects were analyzed for 28 traits--21 type traits, 5 milk production/composition traits, somatic cell score, and productive herdlife. Markers BM415 on chromosome 6 (P = 0.00001) and BM6425 on chromosome 14 (P = 0.00002) were associated with increased protein percentage in a single grandsire family. The latter marker was also associated with changes in milk yield (P = 0.0024) and fat percentage (P = 0.0083) in the same family. Increases in productive herdlife were associated with an allele at BM719 on chromosome 16 (P = 0.0001) in another grandsire family. Selection on these markers may increase genetic gain within these grandsire families when marker-assisted selection is implemented.