|Rexroad Jr, Caird|
Submitted to: Journal of Dairy Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/28/1998
Publication Date: N/A
Interpretive Summary: Our long-term goal is to identify chromosomal regions important for milk production, health, reproduction and type traits in the US commercial Holstein population. Detection of genetic markers located near important gene controlling these traits might be rewarding to breeders and also to researchers for use in marker-assisted selection. The objective of this study was to identify DNA markers that could be used in the selection of bulls. Twenty DNA markers were studied in seven large US Holstein families. Variations with some of these DNA markers were associated with significant effects for protein percentage and productive herdlife in two families. Selection on these markers may increase genetic gain within these families.
Technical Abstract: Quantitative trait loci affecting milk production and composition, health, and type traits were studied in seven large US Holstein grandsire families using the granddaughter design. The families were genotyped at twenty microsatellite markers on 15 chromosomes, and the effects of the marker alleles were analyzed for 28 traits (21 type traits, 5 milk production and composition traits, somatic cell score, and productive herdlife). Markers BM415 on chromosome 6 and BM6425 on chromosome 14 were associated with increased protein percentage in a single grandsire family. The latter marker had a lower probability of being associated with changes in milk yield and fat percentage in the same family. Increases in productive herdlife were associated with an allele at marker BM719 on chromosome 16 in one grandsire family. Selection on these markers may increase genetic gain within these families.