Sepulveda Boris J, Muir Stephanie K, Bolormaa Sunduimijid, Knight Matthew I, Behrendt Ralph, MacLeod Iona M, Pryce Jennie E, Daetwyler Hans D
Agriculture Victoria, AgriBio, Centre for AgriBioscience, Bundoora, VIC, Australia.
School of Applied Systems Biology, La Trobe University, Bundoora, VIC, Australia.
Front Genet. 2022 May 11;13:883520. doi: 10.3389/fgene.2022.883520. eCollection 2022.
Previous studies have shown reduced enteric methane emissions (ME) and residual feed intake (RFI) through the application of genomic selection in ruminants. The objective of this study was to evaluate feeding behaviour traits as genetic indicators for ME and RFI in Australian Maternal Composite ewes using data from an automated feed intake facility. The feeding behaviour traits evaluated were the amount of time spent eating per day (eating time; ETD; min/day) and per visit (eating time per event; ETE; min/event), daily number of events (DNE), event feed intake (EFI; g/event) and eating rate (ER; g/min). Genotypes and phenotypes of 445 ewes at three different ages (post-weaning, hogget, and adult) were used to estimate the heritability of ME, RFI, and the feeding behaviour traits using univariate genomic best linear unbiased prediction models. Multivariate models were used to estimate the correlations between these traits and within each trait at different ages. The response to selection was evaluated for ME and RFI with direct selection models and indirect models with ETE as an indicator trait, as this behaviour trait was a promising indicator based on heritability and genetic correlations. Heritabilities were between 0.12 and 0.18 for ME and RFI, and between 0.29 and 0.47 for the eating behaviour traits. In our data, selecting for more efficient animals (low RFI) would lead to higher methane emissions per day and per kg of dry matter intake. Selecting for more ETE also improves feed efficiency but results in more methane per day and per kg dry matter intake. Based on our results, ETE could be evaluated as an indicator trait for ME and RFI under an index approach that allows simultaneous selection for improvement in emissions and feed efficiency. Selecting for ETE may have a tremendous impact on the industry, as it may be easier and cheaper to obtain than feed intake and ME data. As the data were collected using individual feeding units, the findings on this research should be validated under grazing conditions.
先前的研究表明，通过在反刍动物中应用基因组选择，可以减少肠道甲烷排放（ME）和剩余采食量（RFI）。本研究的目的是利用自动采食量设施的数据，评估澳大利亚母系复合母羊的采食行为性状作为ME和RFI的遗传指标。所评估的采食行为性状包括每天采食时间（采食时间；ETD；分钟/天）和每次采食的时间（每次采食事件的采食时间；ETE；分钟/事件）、每日采食事件数（DNE）、每次采食事件的采食量（EFI；克/事件）和采食速率（ER；克/分钟）。使用单变量基因组最佳线性无偏预测模型，对445只处于三个不同年龄（断奶后、周岁羊和成年羊）的母羊的基因型和表型进行分析，以估计ME、RFI和采食行为性状的遗传力。使用多变量模型估计这些性状之间以及不同年龄各性状内部的相关性。采用直接选择模型和以ETE为指标性状的间接模型，对ME和RFI的选择反应进行评估，因为基于遗传力和遗传相关性，这种行为性状是一个有前景的指标。ME和RFI的遗传力在0.12至0.18之间，采食行为性状的遗传力在0.2至0.47之间。在我们的数据中，选择效率更高的动物（低RFI）会导致每天和每千克干物质摄入量产生更高的甲烷排放。选择更多的ETE也能提高饲料效率，但会导致每天和每千克干物质摄入量产生更多的甲烷。根据我们的研究结果，在允许同时选择以改善排放和饲料效率的指数方法下，ETE可被评估为ME和RFI的指标性状。选择ETE可能会对该行业产生巨大影响，因为获取ETE数据可能比获取采食量和ME数据更容易、成本更低。由于数据是使用个体采食单元收集的，本研究的结果应在放牧条件下进行验证。
