Estimation of genetic parameters for pre-weaning growth traits in Dorper sheep under local Chinese conditions

¹College of Animal Science, Inner Mongolia Agricultural University, Hohhot, China
²Inner Mongolia Sino sheep Technology Co. Ltd, Ulanqab, China
³Key Laboratory of Sheep Genetic Breeding and Reproduction Technology, Ministry of Agriculture and Rural Affairs, Ulanqab, China
⁴Key Laboratory of Mutton Sheep Genetics and Breeding, Ministry of Agriculture, Hohhot, China
⁵Inner Mongolia Key Laboratory of Sheep & Goat Genetics, Breeding and Reproduction, Hohhot, China

Correspondence: Yongbin Liu,Email: Liuyongbin@imau.edu.cn
Yanjun Zhang, Tel: +86-0471-4301619, Email: imauzyj@163.com

Received: 8 August 2025 • Revised: 22 September 2025 • Accepted: 7 November 2025

Abstract

Objective
This study aimed to estimate non-genetic factors, variance components, and genetic parameters (heritability, genetic/phenotypic correlations) for birth weight (BW), weaning weight (WW), average daily gain (ADG), and Kleiber ratio (KR) traits of Dorper sheep under localized Chinese conditions.
Methods
Data from 2,022 Dorper sheep lambs (2019–2021) in Inner Mongolia Sano Sheep Breeding Co., Ltd. were analyzed. Traits included BW, WW (adjusted to 90 days), ADG, and KR. GLM (R 4.3.1) assessed non-genetic factors (recipient dam age, sex, birth year, month, herd). Six animal models were compared using ASReml’s AIREML to determine the optimal model for genetic parameter estimation, with bivariate models analyzing genetic/phenotypic correlations.
Results
Recipient dam age, sex, birth year, month, and herd significantly affected all traits (P<0.05). Model 2 (direct additive genetic and maternal permanent environmental effects) was optimal. Heritability was low (BW: 0.0215; WW: 0.0287; ADG: 0.0391; KR: 0.0504). BW genetically correlated negatively with WW, ADG, and KR; WW showed strong positive genetic correlations with ADG (0.9952) and KR (0.9984), and high phenotypic correlations with them (0.9829 and 0.8819).
Conclusion
Low heritability limit direct selection for pre-weaning traits. Prioritizing WW enhances indirect genetic gains for ADG and KR, aiding the optimization of Dorper sheep breeding strategies under Chinese intensive systems.

Keywords: Dorper sheep; Genetic parameters; Genetic correlation; Phenotypic correlation; Pre-weaning growth traits