What do veterinarians do with the dead pets?

I worked at a vets office for a while and to be honest its a little grim. Once the pet is dead they are wrapped in a plastic bag and left in an industrial freezer, then about once a week a truck comes by to pick them up and then transport them to a cremation facility. I always dreaded having to help load up the truck, the drivers just threw the corpses in the back of the truck. It was difficult seeing the family cry at the loss of their pet and only a few days later see it thrown nonchalantly into a truck. The job was very rewarding in other ways at least.