This study was conducted to find out that how much does it effects as it considered not only animal additive genetic effect but also maternal genetic effect for improving litter traits of pigs. The data of 10,836 records on 2,636 sows in Landrace and 14,463 records on sows in Yorkshire were analyzed which had been measured from 1998 to July 2017 in a nucleus herd of pig population. The traits used on this analysis were total number of born with (TNB2) and without mummy (TNB1) and number of born alive (NBA). Two different multivariate animal mixed models were considered and compared of variance components estimated from these models. The one (Model 1) was set up with assumed to parity, return events and batch effects as fixed and service sire, permanent environment and animal additive genetic effects as random. The other (Model 2) was same with Model 1 except considering maternal additive genetic effects as random. (Co)variance for random effects and genetic parameters were estimated using restricted maximum likelihood method and breeding values as best linear unbiased prediction were estimated using preconditioned conjugate gradient algorithm on each model and breed. From these models, heritability estimates for NBA were about 0.10 and 0.11 on both models in Landrace and Yorkshire, respectively. Forthermore, it was estimated that there were little variations in the maternal genetic effects with roughly 1~2% of total variation. Result from comparing estimated breeding values for each trait between each model, ranking of genetic capability through total breeding values on model 1 and on model 2 showed highly correlated with more than 0.92. Consequently, for improving litter traits, selection based on breeding values by direct genetic effects without considering maternal genetic effects were reccommendable.

ABSTRACT
 Ⅰ. 서론
 Ⅱ. 재료 및 방법
  1. 공시 자료
  2. 통계분석 방법
 Ⅲ. 결과 및 고찰
  1. 일반능력 및 요인분석
  2. 교배웅돈 효과
  3. 영구환경효과
  4. 유전분산 및 유전력
  5. 유전공분산 및 유전상관
  6. 육종가
 Ⅳ. 요약
 Ⅴ. 참고문헌

• 이득환(한경대학교) | Deukhwan Lee (Department of Animal Life Resources, Hankyong National Univerisity) Corresponding author