Submitted to: Journal of Animal Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/13/1999
Publication Date: N/A
Interpretive Summary: Tough beef is an important problem for the cattle industry, especially for cattle containing Brahman, Nelore or Zebu (Bos indicus) germplasm. On the other hand, Bos indicus germplasm confers advantages for heat tolerance, hybrid vigor when crossed with Bos taurus, and resistance to infections and parasites in tropical and subtropical environments. Identification of genes or chromosomal regions responsible for the phenotypic differences between Bos indicus and Bos taurus germplasm would greatly facilitate the development of improved cattle populations with the desirable attributes from both species. We identified a region on bovine chromosome 15 that influences beef tenderness (as measured by Warner-Bratzler shear force) in cattle containing a mixture of Bos indicus and Bos taurus germplasm. This chromosomal region accounted for 26% of the variation in meat tenderness for one slaughter group and less for the others. The effect of this chromosomal region was masked by unknown environmental factors that were apparently more prevalent for some slaughter groups compared to others.
Technical Abstract: A genome scan was conducted using 196 microsatellite DNA markers spanning the 29 autosomal bovine chromosomes and Warner-Bratzler shear force collected at d 2 (WBS2) and 14 (WBS14) postmortem on 294 progeny from one Brahman x Hereford bull mated to Bos taurus cows to identify quantitative trait loci (QTL) for beef tenderness. One QTL was identified and located 28 cM (95% confidence interval is 17 to 40 cM) from the most centromeric marker on BTA15. The QTL interacted strongly with slaughter group. The difference in WBS14 between progeny with the Brahman paternally inherited allele versus those with Hereford was 1.19 phenotypic standard deviations (explained 26% of phenotypic variance) for one slaughter group and was insignificant for three other slaughter groups. Apparently, environmental factors present for three of the four slaughter groups were capable of masking the effect of this QTL. The sensitivity of the QTL effect to environment factors indicates that marker-assisted selection may not be effective. Future research to elucidate the cause of the QTL x slaughter group interaction may lead to improved strategies for controlling variation in meat tenderness via marker-assisted selection, post mortem processing or live animal management.