牲

Left ox radical - the side-form of 牛 (often written 牜), a pictograph of a horned animal's head. The indexing radical, anchors 牲 in the livestock family: 物 thing (originally an ox), 特 special (a bull), 牧 to herd. Marks 牲 as the animals raised to be slaughtered as sacrificial offerings (three 牲: ox, sheep, pig).

Right 生 supplies the sound - shēng exactly, no shift. Also adds a sharp semantic flavor: 'living, alive' - fitting because sacrificial animals were specifically required to be living and whole when offered. Same phonetic family: 性 nature, 姓 surname, 星 star, 笙 mouth-organ. The pairing of ox + living gives 'live livestock,' the defining sense of sacrificial animals.