Verses with the word colt in the Old Testament (3 verses):

Genesis 49:11
Binding his foal unto the vine, and his ass's colt unto the choice vine; he washed his garments in wine, and his clothes in the blood of grapes:

Job 11:12
For vain men would be wise, though man be born like a wild ass's colt.

Zechariah 9:9
Rejoice greatly, O daughter of Zion; shout, O daughter of Jerusalem: behold, thy King cometh unto thee: he is just, and having salvation; lowly, and riding upon an ass, and upon a colt the foal of an ass.