Why does god love sacrifices?

The sacrifices in the Old Testament were a picture of the coming Sacrifice for our sins by Jesus Christ. God's people were being taught about substitutionary death by animal sacrifices. The Lamb represents the "Lamb of God"; Jesus. Without the shedding of Blood; there can be no remission of sin. They did this to show their faith in the truth of the prophecies by God promising to send the Messiah.