When did animal sounds get codified?

They appear to have imitative origin and to refer to different periods around the 16th and 17th century:

Moo (v.):

• "to make the characteristic sound of a cow," 1540s, of imitative origin. Related: Mooed; mooing. The noun is from 1789. Baby-talk moo-cow (n.) attested from 1812.

Meow (n.):

• representation of cat sound, 1842, earlier miaow, miau, meaw (1630s). Of imitative origin, compare French miaou, German miauen, Persian maw, Japanese nya nya, Arabic nau-nau, and Joyce's mrkgnao. In Chinese, miau means "cat." As a verb by 1630s, meaw, also meawle. Compare Old French miauer "to meow, caterwaul."

Bleat apperars to be older in origin:

• *Old English blætan, from West Germanic bhle- (source also of Dutch blaten "to bleat"), of imitative origin (compare Greek blekhe "a bleating; the wailing of children," Old Church Slavonic blejat "to bleat," Latin flere "to weep").