Gave a stock answer?

• Made cattle sounds
• Made a "moo"
• Called from a field
• Emulated a cow
• Emulated bovines
• Sounded like oxen - or their burden?
• Emulated cows
• Made bovine sounds

The Collaborative International Dictionary Word definitions in The Collaborative International Dictionary
Low \Low\ (l[=o]), v. i. [imp. & p. p. Lowed (l[=o]d); p. pr. & vb. n. Lowing .] [OE. lowen, AS. hl[=o]wan; akin to D. loeijen, OHG. hl[=o]jan, hluojan.] To make the calling sound of cows and other bovine animals; to moo. The lowing herd wind slowly o'er ...

Wiktionary Word definitions in Wiktionary
vb. (en-past of: low)