Albert Barnes Commentary Deuteronomy 21:4

"and the elders of that city shall bring down the heifer unto a valley with running water, which is neither plowed nor sown, and shall break the heifer`s neck there in the valley." — Deuteronomy 21:4 (ASV)

Eared - that is, plowed; compare Genesis 45:6 note and references. The word is derived from the Latin, and is in frequent use by English writers of the fifteenth and two following centuries.

Strike off the heifer’s neck - Rather, “break its neck” . The mode of killing the victim distinguishes this lustration from the sin-offering, in which there would be of course shedding and sprinkling of the blood.