宰牛 means 'to slaughter cattle' — a specific, formal verb describing the act of killing cows or bulls for meat, ritual, or other practical purposes. The character 宰 (zǎi) originally meant 'to govern' or 'to oversee', but in classical and modern usage it commonly denotes 'to slaughter' (especially livestock), while 牛 (niú) simply means 'cattle' or 'ox'. Together, 宰牛 is a compound verb that emphasizes the intentional, often skilled or ceremonial, taking of bovine life.

This term appears in agricultural, historical, culinary, and ethical discussions — for example, in descriptions of traditional farming practices, halal/kosher slaughter regulations, or animal welfare debates. It is more precise and formal than general terms like 杀牛 (shā niú), which carries a blunter, less technical connotation. 宰牛 is rarely used in casual daily speech but remains standard in written reports, documentaries, and policy documents concerning livestock management.