Does this apply to all horses?
Malbim: It is horses ready for war.
What is "ha'Erev"?
Rashi: It is their guarantors (allies).
Radak #1: This is like "Erev Rav" (Shemos 12:38), i.e. foreigners from various lands who were in Bavel.
Radak #2: They are merchants. This is like "v'Orvei Ma'aravech" (Yechezkel 27:27). It is as if it says Anshei ha'Erev.
How will they be like women?
Radak: They will be weak, and not fight the enemy.
What will the sword do to the storehouses?
Radak: Perhaps this is like "Ki Charbecha Henafta Aleha" (Shemos 20:22); it is a sword of building and demolition.
Radak citing Targum Yonasan: Those who kill with the sword, they will come to the storehouse and plunder it.