Leviticus 22:26-30

And Jehovah spake unto Moses, saying, When a bullock, or a sheep, or a goat, is brought forth, then it shall be seven days under the dam; and from the eighth day and thenceforth it shall be accepted for the oblation of an offering made by fire unto Jehovah. And whether it be cow or ewe, ye shall not kill it and its young both in one day. And when ye sacrifice a sacrifice of thanksgiving unto Jehovah, ye shall sacrifice it that ye may be accepted. On the same day it shall be eaten; ye shall leave none of it until the morning: I am Jehovah.