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

ADVANCED GENETIC MODELS FOR PIÉTRAIN BOARS INVOLVED IN

CROSSBREEDING IN THE WALLOON REGION USING TEST STATION

AND ON-FARM PHENOTYPIC AND GENOMIC DATA

Contact: marie.dufrasne@ulg.ac.be

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

OBJECTIVE

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:

 _{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:

 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 (37 824 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:

 1 914 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)

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 days

• Live weight at 210 days

• Backfat thickness

• Loin Muscle depth

• Carcass weight

• Meat percentage