The best replacement for foal is colt.

The best alternatives to foal are rated as following:
★★★★★  colt
★★  filly
★★  pony

Your alternative for foal is not listed? Suggest!
Speaking about foal, one probably shouldn't forget about mare.

Other search terms related to foal and their ratings are:
★★★★★ mare
You have in mind a companion for foal and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of foal in all years. Click on graph for more.
foal
colt
filly