Genotype × environment interaction affects sire ranking for live weights in Avikalin sheep

•Evaluation of the genetic models in Avikalin sheep for better accounts of GxE interaction.•RRM is more suitable for genetic analysis of growth data in Avikalin sheep.•Genetic correlations between weights on time points were more towards unity in RRM.•The rankings of breeding values were more consistent in RRM, than in bivariate model.•The RRM was useful to account for GxE for more accurate and unbiased selection. The genotype by environment interaction alters the ranking of the animals at different ages in life due to the changing environment. This affects the selection efficiency of the breeding program. The objective of the present study was to compare the random regression model (RRM) and conventional animal models for better genetic evaluation of the Avikalin sheep. The genetic parameters were estimated for 7274 animals descended from 2418 dams and 409 sires for growth traits of Avikalin sheep, selected over 41 years (1976–2016). The RRM model of choice included a direct genetic, direct maternal, permanent environment for animal and maternal effects. The additive direct heritability (h2) using RRM for live weight at birth (BWT), three months (WWT), six months (6WT), nine months (9WT) and twelve months (12WT) were 0.18 ± 0.02, 0.28 ± 0.02, 0.35 ± 0.02, 0.45 ± 0.02 and 0.36 ± 0.02, respectively. The trends of variances in RRM were comparable to those trends obtained from the inclusive animal model that included the direct genetic, direct maternal and maternal permanent environmental components. The estimates of genetic correlation in RRM were higher (mostly