• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文会议>Conference of The New^Zealand^Society^Of^Animal^Production. >Genetics of alternative definitions of feed efficiency in grazing lactating dairy cows
【24h】

Genetics of alternative definitions of feed efficiency in grazing lactating dairy cows

机译：饲料乳奶牛饲料效率替代定义的遗传学

获取原文
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

The objective of this study was to estimate genetic parameters for measures of energy conversion efficiency (ECE), energy balance (EB), net energy intake (NEI), net energy of lactation (NEL) and body weight (BW), within lactation stages in grazing dairycows. Individual measurements of NEI (n=7,675) from 2,445 lactations on 1,245 grazing cows were available. Residual energy intake (REI) was defined as NEI minus predicted energy requirements; residual energy production (REP) was defined as net energy oflactation (NEL) minus predicted energy requirements. Energy conversion efficiency was defined as NEL divided by NEI; EB was defined as the difference between intake and energy required for maintenance plus lactation. Lactation was divided into three stages (8-90, 91-180, and >180 days in milk [DIM]). Genetic and phenotypic (co)variances for EB, NEL and BW were estimated using univariate and bivariate animal repeatability models. The models included the fixed effects of contemporary group (treatment andtest-date), parity, DIM, as well as a random additive genetic effect of animal, a within-lactation stage random permanent environmental effect and an across-lactation permanent environmental effect. Heritability across-lactation stages varied from 0.13 (8-90 DIM) to 0.28 (91-180 DIM) for NEI, from 0.16 (8-90 DIM) to 0.33 (91-180 DIM) for NEL, from 0.04 (8-90 DIM) to 0.10 (91-180 and >180 DIM) for EB, from 0.03 (8-90 DIM) to 0.11 (>180 DIM) for REI, and from 0.04 (8-90 DIM) to 0.18 (>180 DIM) for ECE. Astrong genetic association between REI and EB was evident when average BW change was close to zero. These genetic parameters from Holstein-Friesian dairy cows fed predominantly grazed grass imply that genetic improvement in selected efficiency traits isachievable.
机译：本研究的目的是估算能量转换效率（ECE），能量平衡（EB），净能量摄入（NEI），泌乳阶（NEL）和体重（BW）的净能量（EB），净能量（BW）的遗传参数在吃草乳制品。可获得1,245奶牛的2,445个哺乳动物的NEI（n = 7,675）的单独测量。残留能量摄入量（REI）定义为NEI负预测能量要求;残留能量产生（REP）定义为缺陷（NEL）减去预测能量要求的净能量。能量转换效率被定义为NEL除以NEI; EB被定义为维护加哺乳期所需的摄入和能量之间的差异。哺乳期分为三个阶段（8-90,91-180，牛奶中的180天）。使用单变量和双变量动物重复性模型估计EB，NEL和BW的遗传和表型（CO）差异。该模型包括当代组（治疗Andtest-Date），平价，暗淡的固定效果，以及动物的随机添加剂遗传效果，泌乳阶段随机的永久环境效应和伴随的永久环境效应。对NEL的0.13（8-90次昏暗）为0.13（8-1-10℃）的遗传性从0.13（8-90次暗淡）变化为0.28（91-1-10次）至0.33（91-180℃），从0.04（8-90 EB的0.10（91-180和> 180次暗淡），从0.03（8-90次）至0.11（> 180次暗淡）的REI，0.04（8-90℃）至0.18（> 180℃）对于ECE。当平均BW变化接近零时，REI和EB之间的Astrong遗传关联是明显的。来自Holstein-Friesian奶牛的这些遗传参数主要放牧的草地，意味着所选择的效率性状的遗传改善即可。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号