Ryan Clodagh V, Pabiou Thierry, Purfield Deirdre C, Kelly David N, Murphy Craig P, Evans Ross D
Irish Cattle Breeding Federation, Ballincollig, Co. Cork, Ireland.
Department of Biological Sciences, Munster Technological University, Bishopstown, Co. Cork, Ireland.
J Anim Sci. 2025 Jan 4;103. doi: 10.1093/jas/skaf162.
With the pressing global challenge of climate change, the potential to breed cattle that produce less lifetime methane offers a transformative solution that is both sustainable and impactful. The objective of this study was to determine the genetic correlations between enteric methane emissions and economically important traits included in the current terminal index used to breed animals for meat in Ireland. This terminal index is typical of terminal-type indexes used globally, constituting traits associated with calving performance, carcass merit, and efficiency traits such as feed intake and age at finish, as well as some ancillary traits such as docility. Methane and carbon dioxide flux measurements recorded from 2018 to 2024 using 10 GreenFeed Emission Monitoring systems in a progeny performance test center on 1,835 beef animals and a more expansive dataset from commercial farmers with phenotypic performance data on calving performance, carcass quality, and efficiency traits were available on up to 402,039 animals for analyses. Five trait definitions for methane and carbon dioxide emissions were derived: individual spot measures, 1-d, 5-d, and 10-d averages of spot measures, and a full test average per animal, where all emission measurements were averaged across the test period. (Co)variance components between all trait definitions and phenotypic performance traits were estimated using animal linear mixed models. Methane emissions were strongly correlated with feed intake ranging from 0.49 (standard error [SE] = 0.119) to 0.76 (SE = 0.057) and carcass weight ranging from 0.44 (SE = 0.050) to 0.50 (SE = 0.060) across trait definitions, suggesting that selection for reduced methane emissions could adversely impact growth and performance. An antagonistic correlation was found between methane and age at finish ranging -0.27 (SE = 0.063) to -0.18 (SE = 0.084), which suggests that animals who have an earlier finishing age produce more methane per day. Carcass conformation was positively weakly correlated with methane (0.09 to 0.12), thus suggesting there is a potential to select for improved carcass conformation with minimal impact on enteric methane emissions. Overall, these findings emphasize the need for breeding strategies that capture the trade-offs between reducing methane emissions and preserving economically valuable traits such as feed intake, carcass weight, and conformation in beef finishing systems.
面对气候变化这一紧迫的全球挑战，培育一生甲烷排放量较低的肉牛具有变革性意义，是一种可持续且有影响力的解决方案。本研究的目的是确定爱尔兰目前用于培育肉牛的终端指数中所包含的肠道甲烷排放与经济重要性状之间的遗传相关性。这个终端指数是全球使用的终端型指数的典型代表，包含与产犊性能、胴体品质以及采食量和育肥年龄等效率性状相关的性状，还有一些辅助性状，如温顺性。2018年至2024年期间，在一个后代性能测试中心，使用10个绿色饲料排放监测系统对1835头肉牛进行了甲烷和二氧化碳通量测量，并且有来自商业养殖户的更广泛数据集，其中包含多达402,039头动物的产犊性能、胴体质量和效率性状的表型性能数据可供分析。得出了甲烷和二氧化碳排放的五个性状定义：个体单点测量值、单点测量值的1天、5天和10天平均值，以及每头动物的完整测试平均值，即所有排放测量值在测试期间进行平均。使用动物线性混合模型估计了所有性状定义与表型性能性状之间的（协）方差分量。在不同的性状定义中，甲烷排放与采食量的相关性很强，范围从0.49（标准误[SE]=0.119）到0.76（SE=0.057），与胴体重的相关性范围从0.44（SE=0.050）到0.50（SE=0.060），这表明选择降低甲烷排放可能会对生长和性能产生不利影响。发现甲烷与育肥年龄之间存在拮抗相关性，范围从-0.27（SE=0.063）到-0.18（SE=0.084），这表明育肥年龄较早的动物每天产生的甲烷更多。胴体形态与甲烷呈弱正相关（0.09至0.12），因此表明有可能在对肠道甲烷排放影响最小的情况下选择改善胴体形态。总体而言，这些发现强调了制定育种策略的必要性，该策略要兼顾减少甲烷排放与保留肉牛育肥系统中采食量、胴体重和形态等经济价值性状之间的权衡。
