Genotype by environment interactions for growth and backfat thickness traits in Yorkshire and Landrace pigs

Genotype by environment interactions (GxE) may reduce the response of performance traits. The aim of this study is to estimate the genetic correlation of the same traits between two genetically linked of Binh Thang farm and Dong A farm. The total of 10 boars, 15 gilts and 442 semen dozes of Yorkshire and Landrace boars had been exchanged between two farms from 2000 to 2007. Records of individual performance test were obtained from 881 Landrace and 652 Yorkshire pigs in Binh Thang farm, and 835 Landrace and 1326 Yorkshire pigs in Dong A farm. Measurements were adjusted to days to 90kg (D90) and backfat (mm) at 90kg liveweight (BF90) referred on the recommendations of NSIF (2002). For Landrace pigs, genetic correlations of the same trait between two environments estimated using REML (restricted maximum likelihood) method in VCE5 software were 0.51 and 0.63 for D90 and BF90 traits, respectively. For Yorkshire pigs, these values were higher, 0.93 for D90 and 0.99 for BF90, respectively. Thus, the evidence of genotype by environment interactions was found in Landrace pigs for measured traits D90 and BF90, while this was not presented in Yorkshire pigs. This means the adaptation to alternative environments in Yorkshire pigs is better than in Landrace pigs.