1系赫里福德公牛阴囊周长和精液特征的遗传参数估计值。

Genetic parameter estimates for scrotal circumference and semen characteristics of Line 1 Hereford bulls.

作者信息

Kealey C G, MacNeil M D, Tess M W, Geary T W, Bellows R A

机构信息

Montana State University, Bozeman, 59717, USA.

出版信息

J Anim Sci. 2006 Feb;84(2):283-90. doi: 10.2527/2006.842283x.

DOI:10.2527/2006.842283x

PMID:16424254

Abstract

The objectives of this study were to estimate heritability for scrotal circumference (SC) and semen traits and their genetic correlations (rg) with birth weight (BRW). Semen traits were recorded for Line 1 Hereford bulls (n = 841), born in 1963 or from 1967 to 2000, that were selected for use at Fort Keogh (Miles City, MT) or for sale. Semen was collected by electroejaculation when bulls were a mean age of 446 d. Phenotypes were BRW, SC, ejaculate volume, subjective scores for ejaculate color, swirl, sperm concentration and motility, and percentages of sperm classified as normal and live or having abnormal heads, abnormal midpieces, proximal cytoplasmic droplets (primary abnormalities), bent tails, coiled tails, or distal cytoplasmic droplets (secondary abnormalities). Percentages of primary and secondary also were calculated. Data were analyzed using multiple-trait derivative-free REML. Models included fixed effects for contemporary group, age of dam, age of bull, inbreeding of the bull and his dam, and random animal and residual effects. Random maternal and permanent maternal environmental effects were also included in the model for BRW. Estimates of heritability for BRW, SC, semen color, volume, concentration, swirl, motility, and percentages of normal, live, abnormal heads, abnormal midpieces, proximal cytoplasmic droplets, bent tails, coiled tails, distal cytoplasmic droplets, and primary and secondary abnormalities were 0.34, 0.57, 0.15, 0.09, 0.16, 0.21, 0.22, 0.35, 0.22, 0.00 0.16, 0.37, 0.00 0.34 0.00, 0.30, and 0.33, respectively. Estimates of rg for SC with color, volume, concentration, swirl, motility, and percentages of live, normal, and primary and secondary abnormalities were 0.73, 0.20, 0.77, 0.40, 0.34, 0.63, 0.33, -0.36, and -0.45, respectively. Estimates of rg for BRW with SC, color, volume, concentration, swirl, motility, and percentages live, normal, and primary and secondary abnormalities were 0.28, 0.60, 0.08, 0.58, 0.44, 0.21, 0.34, 0.20, -0.02, and -0.16, respectively. If selection pressure was applied to increase SC, all of the phenotypes evaluated would be expected to improve. Predicted correlated responses in semen characteristics per genetic SD of selection applied to SC were 0.87 genetic SD or less. If selection pressure was applied to reduce BRW, the correlated responses would generally be smaller but antagonistic to improving all of the phenotypes evaluated. Predicted correlated responses in SC and semen characteristics per genetic SD of selection applied to BRW were less than 0.35 genetic SD.

摘要

本研究的目的是估计阴囊周长（SC）和精液性状的遗传力，以及它们与出生体重（BRW）的遗传相关性（rg）。记录了1963年出生或1967年至2000年出生的1系赫里福德公牛（n = 841）的精液性状，这些公牛被选用于基奥堡（蒙大拿州迈尔斯城）或用于销售。当公牛平均年龄为446天时，通过电刺激采精。表型包括BRW、SC、射精量、射精颜色主观评分、漩涡、精子浓度和活力，以及分类为正常、存活或头部异常、中段异常、近端细胞质滴（主要异常）、弯尾、卷尾或远端细胞质滴（次要异常）的精子百分比。还计算了主要和次要异常的百分比。使用多性状无导数REML分析数据。模型包括当代组、母牛年龄、公牛年龄、公牛及其母牛的近亲繁殖的固定效应，以及随机动物和残差效应。BRW模型中还包括随机母体和永久母体环境效应。BRW、SC、精液颜色、体积、浓度、漩涡、活力以及正常、存活、头部异常、中段异常、近端细胞质滴、弯尾、卷尾、远端细胞质滴以及主要和次要异常百分比的遗传力估计值分别为0.34、0.57、0.15、0.09、0.16、0.21、0.22、0.35、0.22、0.00、0.16、0.37、0.00、0.34、0.00、0.30和0.33。SC与颜色、体积、浓度、漩涡、活力以及存活、正常、主要和次要异常百分比的rg估计值分别为0.73、0.20、0.77、0.40、0.34、0.63、0.33、-0.36和-0.45。BRW与SC、颜色、体积、浓度、漩涡、活力以及存活、正常、主要和次要异常百分比的rg估计值分别为0.28、0.60、0.08、0.58、0.44、0.21、0.34、0.20、-0.02和-0.16。如果施加选择压力以增加SC，则预期所有评估的表型都会改善。针对应用于SC的每个遗传标准差，精液特征的预测相关反应为0.87个遗传标准差或更低。如果施加选择压力以降低BRW，相关反应通常会较小，但与改善所有评估的表型呈拮抗关系。针对应用于BRW的每个遗传标准差，SC和精液特征的预测相关反应小于0.35个遗传标准差。