Cursed burnt offerings

Exodus 20:24 says, “An altar of earth thou shalt make unto me, and shalt sacrifice thereon thy burnt offerings, and thy peace offerings, thy sheep, and thine oxen: in all places where I record my name I will come unto thee, and I will bless thee.”  I thought god only wanted the best of cattle used for burnt offerings.  But in Genesis he said cattle are cursed.  He wants perfect cursed animals offered to him?