Reproductive performance and genetic parameters for Australian Dorset Sheep.
Reproductive performance and genetic parameters for Australian Dorset Sheep.
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澳大利亚多塞特羊的繁殖性能和遗传参数。
DOI：
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发表时间：
1994
期刊：
影响因子：
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通讯作者：
A. Gilmour
中科院分区：
文献类型：
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作者：
L. Brash;N. Fogarty;A. Gilmour
报道了大型多塞特种马群中母羊的繁殖性能。数据包括 2488 只母羊，25 年来有 10016 条加入记录。繁殖性状的平均表现为：受精率 92%，产羔数 1.31 只，新生羔羊存活率 91%，羔羊断奶存活率 85%，每只加入的母羊总体出生羔羊 1.20 只，断奶羔羊 1.02 只。品种之间（无角赛特犬和有角赛特犬）、出生季节（春季和秋季）和交配季节（春季和秋季）之间的差异对于大多数繁殖性状而言是显着的。母羊加入时年龄的线性和二次回归对于所有性状均非常显着（P < 0.001），最大表现在三岁至六岁之间。母羊生殖性状的遗传力估计为：出生羔羊数量为 0.062 ψ 0-02，每只母羊加入的断奶羔羊数量为 0.04 ψ 0.01，组成性状为生育力 0.02 ψ -01，产羔数 0 08 ψ 0 -02，羔羊存活率 0.00 ψ 0.01。所有繁殖性状的重复性估计均小于 0.14，这导致使用重复记录时预测的遗传力显着提高。母羊平均一生性能的遗传力估计值大约有四项记录，出生羔羊为 0.08 | 0 06，断奶羔羊为 0.12 | 0.05，生育力为 0.08 | 0.04，产羔数为 0.19 | 0 -04，羔羊存活率为 0。产羔数与羔羊出生和断奶的遗传相关性接近一致，而繁殖力的遗传相关性较低，并且从出生羔羊（0.6l | 0.22）到断奶羔羊（0-45 | 0.30）呈下降趋势。母羊寿命的估计遗传力（定义为母羊在种羊群中保留的年数）为 0.00 | 0.03。结合文献中的其他报告以及多塞特品种在澳大利亚羔羊产业中的作用，讨论了繁殖率遗传改进的潜力。多塞特鸡群繁殖率的提高会影响种马盈利能力以及通过选择其他性状（例如活重）而获得的遗传改良率。得出的参数估计值将用于编译 LAMBPLAN 中遗传评估的特定品种参数集。
Reproductive performance of ewes in a large Dorset stud flock is reported. The data included 2488 ewes with 10016 joining records over 25 years. Average performance for reproductive traits were: fertility 92%, litter size 1.31, neonatal lamb survival 91%, lamb survival to weaning 85%, with overall lambs born 1.20 and lambs weaned 1.02 per ewe joined. Differences between breeds (Poll Dorset and Dorset Horn), season of birth (spring and autumn) and season of joining (spring and autumn) were significant for most reproduction traits. Linear and quadratic regressions for age of ewe at joining were highly significant for all traits (P < 0.001) with maximum performance between three and six years of age. Estimates of heritability for ewe reproductive traits were: 0.062 ¦ 0-02 for number of lambs born and 0.04 ¦ 0.01 for number of lambs weaned per ewe joined, and component traits, 0.02 ¦0 -01 for fertility, 0 08 ¦ 0 -02 for litter size and 0.00 ¦ 0.01 for lamb survival. Estimates of repeatability were less than 0.14 for all the reproduction traits, which resulted in substantially higher predicted heritabilities when repeated records were used. Heritability estimates for average ewe lifetime performance, with approximately four records, were 0.08 ¦ 0 06 for lambs born, 0.12 ¦ 0.05 for lambs weaned, 0.08 ¦ 0.04 for fertility, 0.l9 ¦ 0 -04 for litter size and zero for lamb survival. The genetic correlations between litter size and lambs born and weaned were close to unity, whereas those for fertility were lower and declined from lambs born (0.6l ¦ 0.22) to lambs weaned (0-45 ¦ 0.30). The estimated heritability for ewe longevity, defined as the number of years the ewe remained in the breeding flock, was 0.00 ¦ 0.03. The potential for genetic improvement in reproductive rate is discussed in relation to other reports in the literature and in the context of the roles of the Dorset breed in the Australian lamb industry. Increased reproductive rate in Dorset flocks impacts on stud profitability and the rate of genetic improvement from selection for other traits such as liveweight. The parameter estimates derived will be used in compiling breed-specific parameter sets for genetic evaluation in LAMBPLAN.