A primary screen of the bovine genome for quantitative trait loci affecting some growth traits of Japanese Black calves.

A primary genomic screen for quantitative trait loci (QTL) affecting growth traits was performed by genotyping 99 and 85 microsatellite markers on 18 and 19 progeny from 2 Japanese Black sires. Traits analyzed were birth weight, weaning weight, yearling weight and average daily gain from birth to weaning. Data were analyzed by generating an F-statistic profile computed at 1-cM intervals for each chromosome by the regression of phenotype on the conditional probability of receiving the allele from the sire. Each sire family was analyzed separately as the markers differed. Data were adjusted for the effects of sex of calf and parity of dam. There was evidence for a QTL of the first sire affecting yearling weight, weaning weight and average daily gain in chromosomes A, B and C. Some putative QTL at or just below the threshold were also detected. Results provided and represented a portion of research work being conducted to identify and characterize QTL affecting growth and body shape traits of Japanese Black calves.