01877nam a2200205 a 450000100080000000500110000800800410001910000150006024501270007526001480020250002660035052009270061665300210154365300160156465300160158070000200159670000230161670000160163970000160165510619242021-03-31       2014    bl uuuu     u01u1 u    #d1 aMOTA, R.R.  aGenomic wide-selection for tick resistance in Hereford and Braford cattle via reaction norm models.h[electronic resource]  aIn: Proceedings of the World Congress on Genetics Applied to Livestock Production, 10., Vancouver, BC, Canada, August 17-22, 2014. p.235.c2014  aAcknowledgments: The authors thank Delta G Connection by providing the data used in this research; Embrapa Southern Region Animal Husbandry and Michigan State University for theoretical and technical support; CAPES, CNPq and FAPEMIG by granting the scholarship.  aABSTRACT. The objective of this study was to compare a conventional genomic model (GBLUP) and its extension to a linear reaction norm model (GLRNM) specifying genotype by environment interaction (G*E) for tick resistance in Brazilian cattle. Tick counts (TC) from 4,363 Hereford and Braford cattle from 146 contemporary groups (CG) were available of which 3,591 animals had BovineSNP50 Illumina v2 BeadChip genotypes. The reaction norm covariate was based on CG estimates of TC from a first-step model. Analysis was conducted based on adapting the single step GBLUP/REML procedure. Five-fold cross validation based on K-means and random partitioning was used to compare the fit of the two models. Cross validation correlations were strong and not significantly different between models for either partitioning strategy. Nevertheless, it seems apparent that G*E for tick infestation exists and can captured by GLRNM models.  aCross validation  aSingle-step  aTick counts1 aTEMPELMAN, R.J.1 aFERNANDO F CARDOSO1 aAGUILAR, I.1 aLOPES, P.S.