Webster's Revised Unabridged Dictionary · 1913

Biestings

Biestings ({not transcribed}) , noun, plural

[Old English bestynge, Anglo-Saxon bȳsting, from bȳst, beost; akin to Dutch biest, Old High German biost, German biest; of unknown origin.]

The first milk given by a cow after calving. — B. Jonson
The thick and curdy milk... commonly called biestings. — Newton. (1574)

Also: Beestings