M. Dufrasne 1,2, V. Jaspart 3, J. Wavreille 4 et N. Gengler 1 1 University of Liège, Gembloux Agro Bio-Tech, Animal Science Unit - Gembloux 2 F.R.I.A. - Brussels 3 Walloon Pig Breeders Association (AWEP) - Ciney 4 Walloon Agricultural Research Centre (CRA-W) - Gembloux A DVANCED GENETIC MODELS FOR P IÉTRAIN BOARS INVOLVED IN CROSSBREEDING IN THE W ALLOON R EGION USING TEST STATION AND ON - FARM PHENOTYPIC AND GENOMIC DATA Contact: RESEARCH SUPPORTED BY THE WALLOON REGION OF BELGIUM CONTEXT  New genetic evaluation program for Walloon Piétrain boars tested in test station  Test station progeny test for production traits (growth, carcass quality traits and feed intake)  On-farm performance test for traits recorded on live pigs (weight and carcass quality traits)  Crossbred progeny from Piétrain sires and Landrace K+ dams O BJECTIVE To develop genetic evaluation models combining test station and on-farm data to estimate the genetic values of Piétrain boars for crossbred performances Growth Data:  live weight from crossbred progeny of Piétrain boars recorded at the test station between 50 and 210 days of age  live weight from purebred and crossbred pigs recorded on-farm between 175 and 250 days of age  Breed types: purebred Piétrain and Landrace (on-farm); crossbred Piétrain X Landrace (test station and on-farm)  Data recorded on females, entire and castrated males  Data standardized for each day of age and pre-adjusted at 210 days to take into account variance heterogeneity Model (Dufrasne et al., 2011): Bi-trait animal model with random regressions using linear splines (knots at 50, 100, 175 and 210 days for test station weight; knots at 175, 210 and 250 days for on-farm weight): y = Xb + Q (Za + Zp) + e y = vector of observations (test station and on-farm weight)e = vector of random residual b = vector of fixed effects (sex, contemporary group (CG), heterosis)Q = matrix of linear spline coefficients a = vector of random additive effectX, Z = incidence matrix p = vector of random permanent environment effect Carcass quality traits Data:  Three traits (backfat thickness (BFa), loin muscle depth (LMD) and meat percentage (%Ma)) recorded on live animals in test station for progeny of tested boars, and on-farm for performance tested pigs ( animal recorded for each traits)  Four traits (backfat thisckness (BFb), meat percentage (%Mb), carcass weight (CW) and conformation index (CONF)) recorded on carcass only for crossbred progeny of boars tested in test station (1 980 animals recorded for each trait)  Breed types: purebred Piétrain and Landrace (on-farm); crossbred Piétrain X Landrace (test station and on-farm)  Data recorded on females, entire and castrated males  Linear pre-adjustment of data at 200 days of age Model: Multitrait animal model: y = Xb + Za + e y = vector of observations (BFa, LMD, %Ma, BFb; %Mb, CW and CONF) b = vector of fixed effects (sex, CG and heterosis for live traits; sex, slaughtdate and heterosis for carcass traits) Feed intake Data:  records of estimated individual feed intake (EFI) only for crossbred progeny of boars tested in test station  Data recorded on female and castrated males  Individualization of records by linear regression on average daily gain (ADG) between 100 and 210 days and on live weight at 100 days (LW100), both expressed in breeding values Model: Unitrait animal model y = Xb +Za + e y = vector of observations (EFI) b = vector of fixed effects (sex and pen; ADG and LW100 as linear covariables) M ATERIAL AND M ETHODS RESULTS  For 75 Piétrain boars already progeny tested until now, breeding values (EBV) were estimated using the data and the models described above.  For the moment Walloon pig breeders receive EBV and associated reliabilities for the following traits to base their selection decisions on: UNDER DEVELOPMENT  Global index combining different traits  Further enhanced models that will allow also estimation of non-additive and crossbreeding effects  Genomic selection of Walloon Piétrain boars using Single Nucleotid Polymorphism (SNP) genotypes to estimate additive, non-additive and crossbreeding effects ADG between 100 and 210 daysLive weight at 210 days Backfat thicknessLoin Muscle depth Carcass weightMeat percentage Conformation IndexFeed conversion ratio