Quantitative traits such as pre-weaning growth is expressed as a result of combined genetic and environmental effects. The phenotypic expression of those traits in offspring is affected by direct genetic effect and sometimes also maternal genetic effect which is the ability of the dam to provide optimum nurturing conditions. The objective of the current study was to estimate genetic parameters for birth weight (BW), weaning weight (WW) and average pre-weaning daily weight gain (ADWG) in Central Anatolian Merino sheep. Observations of 9746 lambs descending from 171 rams and 2045 dams between 2014 and 2020 were included in the study. Generalized linear models were applied to determine the best fitting fixed effects model. Subsequently, the estimations of variance and covariance components were carried out by using the restricted maximum likelihood (REML) procedure applied on an animal linear mixed model including those significant effects on preceding analyses. In general, the direct heritability estimates of the traits were moderate for BW, WW and ADWG as found to be 0.22 ± 0.02, 0.32 ± 0.02 and 0.33 ± 0.02 respectively. On the other hand, maternal heritability estimates were considerably low for all traits with 0.04 ± 0.01 (BW), 0.03 ± 0.01 (WW) and 0.03 $\pm$ 0.01 (ADWG). The genetic correlations between BW and WW was moderate and negative as -0.30 $\pm$ 0.05 whereas, the phenotypic and residual correlations were close to zero. Similarly, the correlations between BW and ADWG were negative for all type of correlations. Especially, a moderate genetic correlation was found between the two traits as -0.37 ± 0.05. As expected, the correlations between WW and ADWG were quite high and positive for all type of correlations. The outcomes of the study will contribute to the world-wide sheep breeding literature with the crossbred performance of Merino and an indigenous sheep breed, as well as its parameters of interest in terms of designing breeding programmes with multi-trait selection indices.

断奶前生长等数量性状是遗传和环境综合作用的结果。这些性状在后代中的表型表达受到直接遗传效应的影响，有时还受到母体遗传效应的影响，这是大坝提供最佳营养条件的能力。本研究的目的是评估出生体重（BW），断奶体重（WW）和断奶前平均日增重（ADWG）的遗传参数。）在安那托利亚中部美利奴绵羊中。研究包括2014年至2020年间从171头公羊和2045座大坝降落的9746只羔羊。应用广义线性模型来确定最佳拟合固定效应模型。随后，通过应用限制线性最大似然（REML）程序对动物线性混合模型进行方差和协方差分量的估计，包括对先前分析的那些重大影响。通常，BW，WW和ADWG的性状直接遗传力估计值适中，分别为0.22±0.02、0.32±0.02和0.33±0.02。另一方面，所有性状的产妇遗传力估计值都非常低，分别为0.04±0.01（BW），0.03±0.01（WW）和0.03$\pm$0.01（ADWG）。BW和WW之间的遗传相关为中度和负值为-0.30$\pm$0.05，而表型和残差的相关性接近于零。类似地，对于所有类型的相关，BW和ADWG之间的相关均为负。特别是，两个性状之间的遗传相关性为-0.37±0.05。不出所料，WW和ADWG之间的相关性很高，并且对于所有类型的相关性都是正的。该研究的结果将为美利奴羊和本土绵羊品种的杂交性能及其在设计具有多性状选择指数的育种计划中感兴趣的参数方面的全球绵羊育种文献做出贡献。