|Smith, Timothy - Tim|
|FERRELL, CALVIN - RETIRED ARS EMPLOYEE|
|JENKINS, THOMAS - RETIRED ARS EMPLOYEE|
|King, David - Andy|
Submitted to: Animal Genetics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/13/2011
Publication Date: 9/4/2012
Citation: Lindholm-Perry, A.K., Kuehn, L.A., Snelling, W.M., Smith, T.P., Ferrell, C.L., Jenkins, T.G., King, D.A., Shackelford, S.D., Wheeler, T.L., Freetly, H.C. 2012. Genetic markers on BTA14 predictive for residual feed intake in beef steers and their effects on carcass and meat quality traits. Animal Genetics. 43:599-603.
Interpretive Summary: Residual feed intake (RFI), the difference between the amount of feed that an animal is expected to consume and the actual amount consumed, is a measure of feed efficiency. The ability to choose animals by their genetic make-up that are more efficient will result in cost savings for producers, as these animals will consume less feed and feed is the most costly portion of beef cattle production. In this study, six genetic markers that are predictive for differences in feed efficiency in beef steers were identified in a region on the bovine chromosome 14. Four of the markers associated with RFI were also significantly associated with average daily weight gain, but none were associated with average daily feed intake. This suggests that these markers affect RFI through variation due to growth or other variables rather than variation in the amount of feed consumed. These markers were also evaluated for their effects on meat quality and carcass traits to determine whether they would impact weight and eating quality. Markers with desirable effects on feed efficiency were associated with lower amounts of fat and most were also associated with higher carcass weights. The markers were not associated with marbling and tenderness, thus they are unlikely to impact beef quality. The markers identified in this study may be useful for the genetic selection of feed efficient cattle; however, they must be validated in additional populations of animals.
Technical Abstract: With the high cost of feed for animal production, genetic selection for animals that metabolize feed more efficiently could result in substantial cost savings for cattle producers. The purpose of this study was to identify DNA markers predictive for differences among cattle for traits associated with feed efficiency. Crossbred steers were fed a high-corn diet for 140 d and average daily feed intake (ADFI), ADG, and residual feed intake (RFI) phenotypes were obtained. A region on chromosome 14 was previously associated with RFI in this population of animals. In order to develop markers with the highest utility for predicting an animal’s genetic potential for RFI, we genotyped additional markers within this chromosomal region. These polymorphisms were genotyped on the same animals (n = 1,066) and tested for association with ADFI, ADG, and RFI. Six markers within this region were nominally significant for RFI. After conservative correction for multiple testing, one marker at 25.09 Mb remained significant. Several of these markers were also significant for ADG, although none were significant after correction. Marker alleles with positive effects on ADG corresponded to lower RFI, suggesting an effect increasing growth without increasing feed intake. All markers were also assessed for their effects on meat quality and carcass traits. All of the markers associated with RFI were significant for adjusted fat thickness (AFT) and three were also significant for hot carcass weight (HCW). Marker alleles associated with lower RFI were also associated with reduced AFT, and if they were significant for HCW, the effect was an increase in weight. These markers may be useful as prediction tools for animals that utilize feed more efficiently; however, validation with additional populations of cattle is required.