Estimation of phenotypic and genetic parameters for productive traits of indigenous chickens of Khorasan province

In this study، records collected for body weight at age 1 (BW1)، 56 (BW56) and 84 d (BW84)، age at sexual maturity (ASM)، first egg weight (EW1)، average of egg weight at first week 12 of production (EW12)، average of egg weight at week 28 (EW28)، 30 (EW30) and 32 (EW32) of laying and egg number during 84 days of laying (EN84) were used to evaluate the effect of environmental factors as well as estimate phenotypic and genetic parameters with the restricted maximum likelihood procedure. Different statistical mixed linear models were applied for each trait using SAS software. For body weight at different ages، generation، hatch number and sex were found to be significant (P<0. 01). Generation and hatch number had no significant effect on ASM، EW1، EW12، EW28 and EN84 while it was significant (P<0. 0001) for EW30 and EW32. (Co) Variances components were estimated based upon animal model using DFREML. Univariate heritability estimates were 0. 59، 0. 41، 0. 24، 0. 26، 0. 15، 0. 14، 0. 05، 0. 09، 0. 12 and 0. 07 for BW1، BW56، BW84، ASM، EW1، EW12، EW28، EW30، EW32 and EN84 respectively. The corresponding multivariate heritability estimates were 0. 64، 0. 4، 0. 34، 0. 29، 0. 16، 0. 38، 0. 35، 0. 4، 0. 49 and 0. 08 respectively. Genetic correlation between BW56 and BW84 was 0. 93. Positive genetic correlations were also found among egg weight traits so that EW12 was highly genetically correlated with EW28 (0. 99)، EW30 (0. 99) and EW32 (0. 98). EN84 and ASM were found to be negatively genetically correlated (-0. 86).