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This Article Full Text (PDF) All Versions of this Article: jas.2008-0876v1 87/1/37    most recent Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Sherman, E. L. Articles by Moore, S. S. Search for Related Content PubMed PubMed Citation Articles by Sherman, E. L. Articles by Moore, S. S.

Fine mapping quantitative trait loci (QTL) for feed intake and feed efficiency in beef cattle

E. L. Sherman^*, J. D. Nkrumah^*,, C. Li^*,, R. Bartusiak^*, B. Murdoch^* and S. S. Moore^*

^* Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB, T6G 2P5, Canada , Igenity Livestock Production Business Unit, Merial Ltd. Agriculture and Agri-Food Canada, Lacombe Research Centre, Lacombe, Alberta, T4L 1W1 Canada

stephen.moore{at}ualberta.ca

Abstract

Feed intake and feed efficiency are economically important traits in beef cattle as feed is the highest variable cost in production. Feed efficiency can be measured as feed conversion ratio (FCR, intake per unit gain) or residual feed intake (RFI, measured as DMI corrected for BW and growth rate, and sometimes a measure of body composition, usually carcass fatness, RFI_bf). The goal of this study was to fine map quantitative trait loci (QTL) for these traits in beef cattle using 2,194 markers on 24 autosomes. The animals used were from 20 half-sib families originating from Angus, Charolais, and University of Alberta Hybrid bulls. A mixed model with random sire and fixed QTL effect nested within sire was used to test each cM along the chromosomes. Threshold levels were determined at the chromosome and genome levels using 20,000 permutations. In total, 4 QTL exceeded the genome-wise threshold of P < 0.001, 3 exceeded at P < 0.01, 17 at P < 0.05, and 30 achieved significance at the chromosome-wise threshold level (at least P < 0.05). No QTL were detected on BTA 8, 16, and 27 above the 5% chromosome-wise significance threshold for any of the traits. Nineteen chromosomes contained RFI QTL significant at the chromosome-wise level. The RFI_bf QTL results were generally similar to those of RFI, the positions being similar, but occasionally the level of significance differing. In comparison to RFI, fewer QTL were detected for both FCR and DMI, 12 and 4 QTL, respectively, at the genome-wise thresholds. Some chromosomes contained FCR QTL, but not RFI QTL, but all DMI QTL were on chromosomes where RFI QTL were detected. The most significant QTL for RFI was located on BTA 3 at 82 cM (P = 7.60 x 10^-5), for FCR on BTA 24 at 59 cM (P = 0.0002), and for DMI on BTA 7 at 54 cM (P = 1.38 x 10^-5). The RFI QTL that showed the most consistent results with previous RFI QTL mapping studies were on BTA 1, 7, 18, and 19. The identification of these QTL provides a starting point to identify genes affecting feed intake and efficiency for use in marker-assisted selection and management.

Key Words: beef cattle • feed efficiency • feed intake • QTL • residual feed intake