Abstract The Dormer is a composite breed and constitutes the most numerous terminal sire breed in South Africa. The Elsenburg Dormer flock is the foundation flock of the breed and is still being maintained at the Elsenburg research farm in the Western Cape province of South Africa. Data from 1943 to 2019 were used to investigate genetic and environmental parameters and trends for early growth traits and lamb survival (LS) in the flock. Yearling live weight- and wool traits were recorded for a shorter period from 2008 to 2018. REML-procedures were used to estimate fixed effects as well as genetic parameters and trends in the flock. The fixed effects of birth year, sex, birth type and age of dam had a significant influence on all the early growth traits. There was an interaction between birth year and sex for most traits. Direct single-trait heritability estimates were 0.15 for birth weight (BW), 0.06 for weaning weight (WW), 0.02 for LS, 0.19 for yearling weight (YW), 0.63 for clean yield, 0.56 for clean fleece weight, 0.59 for staple length, 0.59 for staple strength, 0.60 for coefficient of variation of fibre diameter and 0.80 for fibre diameter. Maternal genetic effects amounted to 0.21 for BW, 0.08 for WW and 0.06 for YW. Dam permanent environmental effects ranged from 0.03 for LS to 0.08 for BW and litter effects from 0.12 for LS to 0.28 for BW. Multi-trait heritability estimates were fairly consistent with the above single-trait estimates. Genetic correlations among live weight traits ranged from low (-0.11) for BW and YW to very high (0.93) for WW and YW. Genetic correlations of YW with wool traits ranged from low to moderate. Genetic correlations among wool traits were mostly consistent with literature estimates for wool breeds. Genetic trends for all weight traits suggested a significant positive trend with time. Expressed relative to the overall phenotypic mean, these trends amounted to 0.12 % for BW, 0.16 % for WW and 0.45 % for YW. The study indicated that all traits were heritable and variable. Purposeful selection for a well-defined objective should allow faster genetic improvement than the annual rates of gain that were realised.

中文翻译：

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Elsenburg Dormer 资源群早期生长和一岁性状的遗传和环境参数和趋势

摘要 Dormer 是一个复合品种，是南非数量最多的终端公猪品种。Elsenburg Dormer 群是该品种的基础群，目前仍在南非西开普省的 Elsenburg 研究农场饲养。1943 年至 2019 年的数据用于调查遗传和环境参数以及羊群早期生长性状和羔羊存活率 (LS) 的趋势。从 2008 年到 2018 年的较短时期内记录了一岁鸡的活重和羊毛性状。REML 程序用于估计鸡群的固定效应以及遗传参数和趋势。出生年份、性别、出生类型和坝龄的固定效应对所有早期生长性状都有显着影响。大多数特征的出生年份和性别之间存在相互作用。出生体重 (BW) 的直接单性状遗传力估计值为 0.15，断奶体重 (WW) 为 0.06，LS 为 0.02，一岁体重 (YW) 为 0.19，净产量为 0.63，净羊毛重为 0.56，短纤维长度为 0.59 ，短纤维强度为 0.59，纤维直径变异系数为 0.60，纤维直径为 0.80。BW 的母体遗传效应为 0.21，WW 为 0.08，YW 为 0.06。大坝永久环境影响范围从 LS 的 0.03 到 BW 的 0.08，垃圾影响范围从 LS 的 0.12 到 BW 的 0.28。多性状遗传力估计与上述单性状估计相当一致。体重性状之间的遗传相关性从 BW 和 YW 的低 (-0.11) 到 WW 和 YW 的非常高 (0.93)。YW与羊毛性状的遗传相关性从低到中等。羊毛性状之间的遗传相关性大多与文献中对羊毛品种的估计一致。所有体重性状的遗传趋势表明随着时间的推移呈现显着的积极趋势。相对于整体表型平均值表示，这些趋势为 BW 的 0.12%、WW 的 0.16% 和 YW 的 0.45%。研究表明，所有性状都是可遗传的和可变的。为明确定义的目标进行有目的的选择应该允许比实现的年增益更快的遗传改良。研究表明，所有性状都是可遗传的和可变的。为明确定义的目标进行有目的的选择应该允许比实现的年增益更快的遗传改良。研究表明，所有性状都是可遗传的和可变的。为明确定义的目标进行有目的的选择应该允许比实现的年增益更快的遗传改良。