Richardson C M, Amer P R, Quinton C, Crowley J, Hely F S, van den Berg I, Pryce J E
Agriculture Victoria Research, AgriBio, Centre for AgriBioscience, Bundoora, Victoria 3083, Australia; School of Applied Systems Biology, La Trobe University, Bundoora, Victoria 3083, Australia.
AbacusBio Limited, P.O. Box 5585, Dunedin, New Zealand.
J Dairy Sci. 2022 May;105(5):4272-4288. doi: 10.3168/jds.2021-21277. Epub 2022 Feb 25.
This research explores possible options to reduce greenhouse gas (GHG) emissions in the Australian dairy industry by (1) including an environmental component in the national breeding program and (2) estimating the economic and environmental impacts of implementation of the subsequent indexes. A total of 12 possible selection indexes were considered. These indexes were developed to predict changes in gross per-animal methane production (using 3 scenarios depending on availability and efficacy of a direct methane trait breeding value prediction) with 4 different carbon prices, integrating them into an augmentation of the current conventional national selection index. Although some economic response is lost with inclusion of the GHG subindexes in the Balanced Performance Index, options do exist where this loss is marginal and, even in scenarios where all selection pressure is based on the environmental weighting, economic progress is still made in all cases. When including environmental traits within an index, if a relatively low percentage of economic gain or index progression is sacrificed, then approximately 40 to 50% of the maximum possible reductions in emissions may be achieved. This concurrent selection of estimated breeding values that have a correlated favorable response in emissions in addition to direct selection on a residual methane trait allows a high level of methane reduction to be achieved with a realized cost to farmers that is far lower than the economic value placed on carbon. By implementing a GHG subindex in the national breeding program, we can achieve up to a 7.9% decrease in residual methane and 9 times the reduction in gross emissions in 10 yr, compared with the current breeding program, with little to no cost to farmers. By 2050, selection based on one of the more moderate index scenarios at a carbon price of AUD$250/t (AUD$1 = US$0.71), or opportunity cost to farmers of AUD$87.22, will reduce gross emissions by 8.23% and emissions intensity by 21.25%, therefore offering a mitigation strategy that will be effective at reducing emissions with little compromise to profit.
本研究探索了澳大利亚乳业减少温室气体（GHG）排放的可能选项，具体包括：（1）在国家育种计划中纳入环境因素；（2）评估后续指标实施的经济和环境影响。共考虑了12种可能的选择指数。这些指数旨在预测每头动物甲烷总排放量的变化（根据直接甲烷性状育种值预测的可用性和有效性采用3种情景），并结合4种不同的碳价格，将其纳入当前传统国家选择指数的扩充版本。尽管在平衡性能指数中纳入温室气体子指数会导致一定的经济响应损失，但仍存在一些选项，其中这种损失微不足道，而且即使在所有选择压力都基于环境权重的情景下，所有情况下仍能取得经济进展。当在指数中纳入环境性状时，如果牺牲的经济收益或指数进展比例相对较低，那么可能实现约40%至50%的最大可能减排量。除了直接选择残余甲烷性状外，同时选择在排放方面具有相关有利响应的估计育种值，能够在农民实现成本远低于碳经济价值的情况下，实现高水平的甲烷减排。通过在国家育种计划中实施温室气体子指数，与当前育种计划相比，我们能够在10年内实现残余甲烷减少7.9%，总排放量减少9倍，且对农民几乎没有成本。到2050年，以每吨250澳元（1澳元 = 0.71美元）的碳价格或农民87.22澳元的机会成本，基于一种较为温和的指数情景进行选择，将使总排放量减少8.23%，排放强度减少21.25%，因此提供了一种减排策略，既能有效减少排放，又几乎不会对利润造成影响。
