Albert Barnes Commentary Zechariah 14:15

"And so shall be the plague of the horse, of the mule, of the camel, and of the ass, and of all the beasts that shall be in those camps, as that plague." — Zechariah 14:15 (ASV)

And so shall be the plague of the Lord ... - Dionysius: “So, when God sends the plague, all the irrational animals of antichrist and his satellites shall perish as the previously mentioned men, who used them, perished. For, for the sins of men, God, to their greater confusion, sometimes slays their beasts, sometimes also for their loving correction.” “The imagery is from the Mosaic law of the ban.

If a whole city became guilty of idolatry, not only the inhabitants but also the beasts were to be destroyed (Deuteronomy 13:15), so that here, in miniature, should be repeated the relation of the irrational to the rational part of the creation, according to which, for the sins of men, the creature is, against its will, made subject to vanity. It is also analogous that in the offense of Achan (Joshua 7:24–25), besides him and his children, his oxen, donkeys, and sheep were (stoned and) burned with him.”