Variance components estimation for farrowing traits of three purebred pigs in Korea

Abstract

ObjectiveThis study was conducted to estimate breed-specific variance components for total number born (TNB), number born alive (NBA) and mortality rate from birth through weaning including stillbirths (MORT) of three main swine breeds in Korea. In addition, the importance of including maternal genetic and service sire effects in estimation models was evaluated.MethodsRecords of farrowing traits from 6,412 Duroc, 18,020 Landrace, and 54,254 Yorkshire sows collected from January 2001 to September 2016 from different farms in Korea were used in the analysis. Animal models and the restricted maximum likelihood method were used to estimate variances in animal genetic, permanent environmental, maternal genetic, service sire and residuals.ResultsThe heritability estimates ranged from 0.072 to 0.102, 0.090 to 0.099, and 0.109 to 0.121 for TNB; 0.087 to 0.110, 0.088 to 0.100, and 0.099 to 0.107 for NBA; and 0.027 to 0.031, 0.050 to 0.053, and 0.073 to 0.081 for MORT in the Duroc, Landrace and Yorkshire breeds, respectively. The proportion of the total variation due to permanent environmental effects, maternal genetic effects, and service sire effects ranged from 0.042 to 0.088, 0.001 to 0.031, and 0.001 to 0.021, respectively. Spearman rank correlations among models ranged from 0.98 to 0.99, demonstrating that the maternal genetic and service sire effects have small effects on the precision of the breeding value.ConclusionModels that include additive genetic and permanent environmental effects are suitable for farrowing traits in Duroc, Landrace, and Yorkshire populations in Korea. This breed-specific variance components estimates for litter traits can be utilized for pig improvement programs in Korea.

Estimation of genetic parameters for farrowing traits in purebred Landrace and Large White pigs

“…These results were in agreeance with those previously estimated in the same breeds using a repeatability model (e.g., Damgaard et al, 2003;Farkas et al, 2007;Lopez et al, 2017). GL showed a heritability of approximately 0.3, which was the highest value obtained as the heritability in this study.…”

“…Negative associations have been reported between litter size and individual birth weight in some studies (Kerr & Cameron, 1995;Roehe, 1999;Sorensen, Vernersen, & Andersen, 2000). The heritability of NBA has been estimated to be low in the previous studies (e.g., Damgaard, Rydhmer, Løvendahl, & Grandinson, 2003;Farkas et al, 2007;Lopez, Kim, Makumbe, Song, & Seo, 2017). It is useful for genetic improvement of NBA to find a trait having heritability higher than, and showing an advantageous genetic correlation with NBA.…”

Genetic parameters for litter traits at different parities in purebred Landrace and Yorkshire pigs

“…The heritability for the TNB and NBA were 0.136 and 0.128 for Landrace pigs, and 0.123 and 0.116 for the Yorkshire breed, respectively. These estimates were slightly higher than those previously reported (Lopez et al, 2017), which could be brought about by the differences in the number of animals and statistical models that were used in these two different studies. The heritability estimates were 0.070 and 0.079 for MORT, 0.078 and 0.083 for NSB and 0.041 and 0.033 for MUM in the Landrace and Yorkshire breeds, respectively.…”

“…In our previous research, we estimated genetic parameters for litter traits using a repeatability model and reported low heritability estimates in the studied population (Lopez, Kim, Makumbe, Song, & Seo, ). Hence, the best possible model has to be defined in order to establish efficient selection programs.…”

Genetic parameter estimation for number born alive at different parities in Landrace and Large White pigs

“…Fitting a single‐trait repeatability model to records at different parities assumes that these are repeated measurements of the same trait. But the response to selection using this model was low in some cases, because not only is the heritability of NBA low (e.g., Damgaard, Rydhmer, Løvendahl, & Grandinson, ; Lopez, Kim, Makumbe, Song, & Seo, ; Ogawa et al, ), but possibly also the records at different parities were not considered as those for genetically different traits (e.g., Baselga, Gomez, Cifre, & Camacho, ; Irgang, Fávero, & Kennedy, ). Several authors hypothesized that partly different genes control reproductive traits in successive parities (Hermesch, Luxford, & Graser, ; Noguera, Varona, Babot, & Estany, ; Roehe & Kennedy, ).…”