Pr

1
Advanced genetic models for Piétrain boars
involved in crossbreeding in the Walloon Region
using test station and on-farm phenotypic and
genomic data 
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
Objective To develop genetic evaluation models
combining test station and on-farm data to
estimate the genetic values of Piétrain boars for
crossbred performances

• 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

• Growth
• Data
• 17 483 live weight from 2 076 crossbred progeny
  of Piétrain boars recorded at the test station
  between 50 and 210 days of age
• 54 068 live weight from 50 824 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
  effect X, Z incidence matrix
• p vector of random permanent
  environment effect
• Carcass quality traits
• Data

Material and Methods

• 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
• 
  

ADG between 100 and 210 days Live weight at 210 days
Backfat thickness Loin Muscle depth
Carcass weight Meat percentage
Conformation Index Feed conversion ratio

• 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

RESEARCH SUPPORTED BY THE WALLOON REGION OF
BELGIUM
Contact marie.dufrasne_at_ulg.ac.be