ASAS/ADSA Growth and Development: Conjugated Linoleic Acid (CLA) in Milk Production, Growth, and Health

throcyte antigen loci covering the whole genome. De-regressed breeding values were available for 29 traits, including 20 conformation, 2 fertility, 4 birth, 2 workability, and 1 longevity trait. After determining the most likely marker haplotypes for all grandsires based on the genotypes of their sons, multi-marker regression analysis of the trait data was used to scan the genome for QTL. Chromosome-wise and experiment-wise significance thresholds were determined by permutation test. The test statistic exceeded the genome-wise significance threshold with a type I error of less then 10% for the following traits and chromosomes: rump width on chromosome 1; feet and legs, foot angle, teat placement, udder, and udder depth on chromosome 6; calving difficulties on chromosome 8; teat length on chromosome 13; rate of stillbirth on chromosome 18, and milking speed and temperament on chromosome 29. All QTL on chromosome 6, that exceeded the genome-wise significance threshold, were located around 88 cM. QTL for rump width on chromosome 1 may have an effect on calving difficulties. QTL for udder traits on chromosome 6 and 13 may affect somatic cell score and mastitis resistance. If there are no unfavorable correlations with other economic traits, marker assisted selection using markers associated with these QTL can be applied.