Animal Breeding and Genomics Group, Wageningen University & Research, PO Box 338, 6700 AH Wageningen, the Netherlands.
Animal Breeding and Genomics Group, Wageningen University & Research, PO Box 338, 6700 AH Wageningen, the Netherlands.
J Dairy Sci. 2023 Jun;106(6):4121-4132. doi: 10.3168/jds.2022-22735. Epub 2023 Apr 18.
To reduce methane (CH) emissions of dairy cows by animal breeding, CH measurements have to be recorded on thousands of individual cows. Currently, several techniques are used to phenotype cows for CH, differing in costs and applicability. However, there is uncertainty about the agreement between techniques. To judge the similarity and repeatability between measurements of different recording techniques, the repeatability, heritability, and genetic correlation are useful metrics. Therefore, our objective was to estimate (1) the repeatability and heritability for CH and carbon dioxide production recorded by GreenFeed (GF) and for CH and carbon dioxide concentration measured by cost-effective but less accurate sniffers, and (2) the genetic correlation between CH recorded with these 2 different on farm and high throughput techniques. Data were available from repeated measurements of CH production (grams/day) by GF units and of CH concentration (ppm) by sniffers, recorded on commercial dairy farms in the Netherlands. The final data comprised 24,284 GF daily means from 822 cows, 170,826 sniffer daily means from 1,800 cows, and 1,786 daily means from 75 cows by both GF and sniffer (in the same period). Additionally, CH records were averaged per week. For daily and weekly mean GF CH the heritabilities were 0.19 ± 0.02 and 0.33 ± 0.04, and for daily and weekly mean sniffer CH the heritabilities were similar and were 0.18 ± 0.01 and 0.32 ± 0.02, respectively. Phenotypic correlations between GF CH production and sniffer CH concentration were moderate (0.39 ± 0.03 for daily means and 0.37 ± 0.05 for weekly means). However, genetic correlations were high; 0.71 ± 0.13 for daily means and 0.76 ± 0.15 for weekly means. The high genetic correlation indicates that selection on low CH concentrations (ppm) recorded by the cost-effective sniffer method, will result in reduced CH production (grams/day) as recorded with GF.
为了通过动物育种减少奶牛的甲烷（CH）排放，必须对数以千计的个体奶牛进行 CH 测量。目前，有几种技术用于对奶牛进行 CH 表型分析，这些技术在成本和适用性上有所不同。然而，对于这些技术之间的一致性存在不确定性。为了判断不同记录技术的测量值之间的相似性和可重复性，重复性、遗传性和遗传相关性是有用的指标。因此，我们的目标是估计：（1）通过 GreenFeed（GF）记录的 CH 和二氧化碳产生量以及通过经济有效的但准确性较低的嗅探器测量的 CH 和二氧化碳浓度的重复性和遗传性；（2）这 2 种不同的农场和高通量技术记录的 CH 之间的遗传相关性。数据来自荷兰商业奶牛场对 GF 单位记录的 CH 产量（克/天）和嗅探器记录的 CH 浓度（ppm）的重复测量。最终数据包括 822 头奶牛的 24284 个 GF 日均值、1800 头奶牛的 170826 个嗅探器日均值以及 75 头奶牛的 GF 和嗅探器的 1786 个日均值（同一时期）。此外，CH 记录按周平均。对于每日和每周平均的 GF CH，遗传性分别为 0.19 ± 0.02 和 0.33 ± 0.04，对于每日和每周平均的嗅探器 CH，遗传性相似，分别为 0.18 ± 0.01 和 0.32 ± 0.02。GF CH 产量和嗅探器 CH 浓度之间的表型相关性为中度（每日均值为 0.39 ± 0.03，每周均值为 0.37 ± 0.05）。然而，遗传相关性很高；每日均值为 0.71 ± 0.13，每周均值为 0.76 ± 0.15。高遗传相关性表明，对经济有效的嗅探器方法记录的低 CH 浓度（ppm）进行选择，将导致 GF 记录的 CH 产量（克/天）减少。
