Submitted to: Joint Abstracts of the American Dairy Science and Society of Animal Science
Publication Type: Abstract Only
Publication Acceptance Date: 4/30/2008
Publication Date: 7/7/2011
Citation: Marquez, G.C., Enns, R.M., Grosz, M.D., MacNeil, M.D. 2011. QTL with dominance effect affecting residual feed intake on BTA6. Joint Abstracts of the American Dairy Science and Society of Animal Science. Journal of Animal Science 86(E-Suppl. 2):362. Abstract #412. Interpretive Summary: abstract only
Technical Abstract: Residual feed intake (RFI) is a measure of feed efficiency and therefore an economically relevant trait. A genome-wide scan for quantitative trait loci (QTL) affecting RFI in beef cattle was conducted. Approximately equally spaced microsatellite markers (n = 229) spanned the 29 bovine autosomes. Two half-sib families of backcross progeny were produced by mating two F*1 Line 1 Hereford (L1) x composite gene combination (CGC) bulls to L1 and CGC cows. Progeny of the first sire were born in 1996 (n=155) and of the second sire were born in 1997 (n=120). Phenotypic data on feed intake and weight gain was collected in 1997 and 1998 for the two calf crops. Due to serial harvest for collection of carcass data, time on feed varied from 82 to 167 days. RFI was calculated as the residual after fitting the regression of daily feed intake on average daily gain, average weight, sex, and year of birth. Genotypes and phenotypes were collected from 218 animals. The backcross progenies from L1 and CGC females were analyzed separately using composite interval mapping. In the backcross to L1 cows, evidence for a QTL affecting RFI was found on BTA6 with a LOD score of 3.2 at 58 cM. Substitution of the L1 allele for the CGC allele reduced RFI by 0.9 kg/d. This QTL was absent in the backcross to CGC cows. Presence of an allele substitution effect in one backcross, but not the other, is consistent with the dominance model of inheritance. Thus, these results indicate a putative QTL with dominance effect on RFI located at approximately 58 cM on BTA6.