What does Deuteronomy 15:19 mean?

Every firstborn male from your cattle and sheep belongs to God. Don’t use them for your own work—don’t put your firstborn ox to work, and don’t shear your firstborn sheep. Deuteronomy 15:19 - Modern Text Bible

(This verse sets apart the firstborn male animals as belonging to God, not for personal use or profit. It’s about remembering that everything you have comes from Him.)