Investigating maternal effects on production traits in Duroc pigs using animal and sire models

Abstract

Variance components for production traits were estimated using different models to evaluate maternal effects. Data analysed were records from the South African pig performance testing scheme on 22 224 pigs from 18 herds, tested between 1990 and 2008. The traits analysed were backfat thickness (BFAT), test period weight gain (TPG), lifetime weight gain (LTG), test period feed conversion ratio (FCR) and age at slaughter (AGES). Data analyses were performed by REML procedures in ASREML, where random effects were successively fitted into animal and sire models to produce different models. The first animal model had one random effect, the direct genetic effects, while the additional random effects were maternal genetic and maternal permanent environmental effects. In the sire model, the random effects fitted were sire and maternal grand sire effects. The best model considered the covariance between direct and maternal genetic effects or between sire and maternal grand sire effects. Fitting maternal genetic effects into the animal model reduced total additive variance, while the total additive variance increased when maternal grand sire effects were fitted into the sire model. The correlations between direct and maternal genetic effects were all negative, indicating antagonism between these effects, hence the need to consider both effects in selection programmes. Direct genetic correlations were higher than other correlations, except for maternal genetic correlations of FCR with TPG, LTG and AGES. There has been direct genetic improvement and almost constant maternal ability in production traits as shown by trends for estimated (EBVs) and maternal breeding values (MBVs), while phenotypic trends were similar to those for EBVs. These results suggest that maternal genetic effects should be included in selection programmes for these production traits. Therefore, the animal-maternal model may be the most appropriate model to use when estimating genetic parameters for production traits in this population.

Estimation of direct and maternal genetic parameters for individual birth weight, weaning weight, and probe weight in Yorkshire and Landrace pigs1

“…The correlation between the direct and maternal genetic effects for BW, BW, and PW in the Yorkshire and Landrace breeds was moderate and negative. These moderate and negative correlations were in agreement with the literature (Arango et al, 2006;Roehe et al, 2010;Dube et al, 2014;Dufrasne et al, 2014). The negative correlation between the direct and maternal genetic effects suggest antagonism between these effects.…”

Estimation of genetic parameters and accuracy of genomic prediction for production traits in Duroc pigs

“…These estimates Cabling et al (2015) in 690 finishing Duroc pigs (0.65, 0.41 and 0.73 for BF, LMA and LP, respectively). Moreover, Do et al (2013) and Dube et al (2014) reported an estimate of heritability of 0.54 and 0.48 for BF, respectively. However, Guo et al (2016) estimated the heritability for BF ranging from 0.30 to 0.32.…”

Maternal effect on body measurement and meat production traits in purebred Duroc pigs

“…It might be beneficial for efficient breeding that some traits are affected by maternal genetic effect (David et al., 2015; Roehe & Kennedy, 1993; Satoh et al., 2002), although we cannot suggest why a non‐zero direct‐maternal genetic correlation was estimated only for BL. Interpreting negative estimates of direct‐maternal genetic correlation has been discussed in terms of biological mechanism, data structure and other factors (Bijma, 2006; David et al., 2015; Dodenhoff, Van Vleck, & Wilson, 1999; Dube et al., 2014; Heydarpour, Schaeffer, & Yazdi, 2008; Lee & Pollak, 1997; Maniatis & Pollott, 2003; Robinson, 1996; Willham, 1980). As an additional analysis, we ran 200 simulations of the phenotypic data of 2,835 pigs with a direct heritability of 0.3 and without maternal genetic or common litter environmental effect, based on the pedigree information of 11,631 pigs, with an infinitesimal model (Bulmer, 1980).…”

“…Substantial effects of a shared environment on phenotypic measurements in younger pigs have been reported, such as common litter environmental effects and maternal genetic effects (Flori et al., 2011; Hoque, Suzuki, Kadowaki, Shibata, & Oikawa, 2007; Suzuki et al., 2005; Tomiyama, Kanetani, Tatsukawa, Mori, & Oikawa, 2010; Yang et al., 2018). Statistical models that ignore maternal effects might bias estimates of direct heritability (Dube, Mulugeta, & Dzama, 2014; Satoh, Hicks, Ishii, & Furukawa, 2002). Therefore, it is important to choose an appropriate model for accurate genetic parameter estimation.…”