Man, it was hard on the livestock!

The Old Testament is full of animal sacrifice including God's very detailed instructions on how to carry it out. Why? What possible benefit is it to God for humans to slaughter animals and then burn them? Does God really enjoy the pleasant aroma? Wasn't it very hard for early worshipers to afford? And what about the animals that paid the ultimate price for the redemption of sins they certainly did not commit?

There is a lot of brutally in the Old Testament mostly ordered by God. This does not seem like the God of the New Testament who is a God of Love and Mercy. Could anyone please reconcile the two versions of God or at least explain it to a struggling believer? I do understand that Jesus' sacrifice on the cross was the ultimate sacrifice - precluding the need for more animal sacrifices today. But, I am having a hard time with all this slaughter in the Old Testament. The animals really paid a price for our redemption! I have previously excused it, personally, by the times - this was a LONG time ago. The transition from a former pagan society to one under God and Christ must have been trying and I suppose the move from former pagan rituals, like animal sacrifice, must have been hard and took some time. Is that explanation good enough?