Exodus 22:30
You are to do the same with your oxen and your sheep. They shall be with their mother for seven days and then on the eighth day you are to give them to me.
Leviticus 22:27
"Whenever a bull, a sheep, or a goat is born, it is to remain for seven days under the care of its mother. But on the eighth day onwards, it may be accepted as an offering made by fire to the LORD.
Deuteronomy 15:19
"Set apart for the LORD your God every firstborn male among your herd and flock. You must not put the firstborn of your ox to work or shear the firstborn of your flock.
Exodus 13:12
you are to dedicate to the LORD everything that first opens the womb. All the firstborn males of your livestock belong to the LORD.
Leviticus 12:3
On the eighth day, the flesh of the baby's foreskin is to be circumcised.