University of Guilan Animal Production Research 2252-0872 3 4 2015 02 20 Genetic analysis of body weight traits in native sheep of Guilan province Genetic analysis of body weight traits in native sheep of Guilan province 63 73 22 FA B. Eteqadi Graduated MS.c student, Department of Animal Science, Faculty of Agricultural Sciences, University of Guilan N. Ghavi Hossein-Zadeh Assistant Professor, Department of Animal Science, Faculty of Agricultural Sciences, University of Guilan A. A. Shadparvar Associate Professor, Department of Animal Science, Faculty of Agricultural Sciences, University of Guilan M. Golshani Expert in Jihad-e-Agriculture Organization of Guilan, Rasht, Iran Journal Article 2015 05 05 The objective of the present study was to estimate genetic parameters of body weight traits in Guilan sheep. Traits included were birth weight (BW, n=14549), 3-month weight (3MW, n=13153) and 6-month weight (6MW, n=10142). Data and pedigree information used in this study were collected during 1994 to 2012 by the Agriculture Organization of Guilan Province in Iran. The GLM procedure of SAS was used for determining the fixed effects which had significant influence on the traits under study. Herd-year-season of lambing had significant effect on under study traits. Genetic parameters were estimated with 6 different animal models using restricted maximum likelihood (REML) procedure of Wombat program. The most suitable model amongst all six models was determined based on Akaike’s Information Criterion (AIC). Results indicated the model 4 was the most appropriate model for weight traits which included direct additive and maternal genetic effects. Based on the most appropriate fitted model, direct and maternal heritabilities of BW, 3MW and 6MW were estimated to be 0.14, 0.27, 0.37, and 0.04, 0.02 and 0.03, respectively. Estimates of direct genetic correlations were 0.08, 0.01 and 0.12 between BW-3MW, BW-6MW and 3MW-6MW, respectively. Estimates of phenotypic correlations were 0.07, -0.01 and -0.30 between BW-3MW, BW-6MW and 3MW-6MW, respectively. The results of this study showed that maternal effects are significant sources of variation for body weight traits and ignoring maternal effects in the model would cause inaccurate genetic evaluation of weight traits. Also genetic progress for body weight traits is possible by selection in Guilan sheep. The objective of the present study was to estimate genetic parameters of body weight traits in Guilan sheep. Traits included were birth weight (BW, n=14549), 3-month weight (3MW, n=13153) and 6-month weight (6MW, n=10142). Data and pedigree information used in this study were collected during 1994 to 2012 by the Agriculture Organization of Guilan Province in Iran. The GLM procedure of SAS was used for determining the fixed effects which had significant influence on the traits under study. Herd-year-season of lambing had significant effect on under study traits. Genetic parameters were estimated with 6 different animal models using restricted maximum likelihood (REML) procedure of Wombat program. The most suitable model amongst all six models was determined based on Akaike’s Information Criterion (AIC). Results indicated the model 4 was the most appropriate model for weight traits which included direct additive and maternal genetic effects. Based on the most appropriate fitted model, direct and maternal heritabilities of BW, 3MW and 6MW were estimated to be 0.14, 0.27, 0.37, and 0.04, 0.02 and 0.03, respectively. Estimates of direct genetic correlations were 0.08, 0.01 and 0.12 between BW-3MW, BW-6MW and 3MW-6MW, respectively. Estimates of phenotypic correlations were 0.07, -0.01 and -0.30 between BW-3MW, BW-6MW and 3MW-6MW, respectively. The results of this study showed that maternal effects are significant sources of variation for body weight traits and ignoring maternal effects in the model would cause inaccurate genetic evaluation of weight traits. Also genetic progress for body weight traits is possible by selection in Guilan sheep. https://ar.guilan.ac.ir/article_22_e99c38d66cb93fdc91a4958ee86b9999.pdf