Thomas Aquinas identifies in ST q. 102, a. 3 the six kinds of sacrificial victims in the Old Testament and explains how each is type of Christ as a the sacrificial victim for the sins of the world. He cites the gloss:

It was fitting that these animals should be offered, that they might foreshadow Christ.

Christ is offered:

1. in the calf, to denote the strength of the cross;
2. in the lamb, to signify His innocence;
3. in the ram, to foreshadow His headship;
4. and in the goat, to signify the likeness of ‘sinful flesh’
5. The turtledove and dove denoted the union of the two natures”; or else the turtledove signified chastity; while the dove was a figure of charity.
6. The wheat-flour foreshadowed the sprinkling of believers with the water of Baptism.”

I particularly like how water is related to the wheat-flour as a sign of baptism.