Effects of Brown Seaweed (Ascophyllum nodosum) Supplementation on Enteric Methane Emissions, Metabolic Status and Milk Composition in Peak-Lactating Holstein Cows

褐藻（Ascophyllum nodosum）补充剂对泌乳高峰期荷斯坦奶牛肠道甲烷排放、代谢状态和牛奶成分的影响