With the avg sport-bike in the 400lb range, and the average adult male being somewhere between 150 and 200, I doubt it was a 550-600lb deer, but it would be scary as shit nonetheless.
Yearling bucks average 150 pounds, while does of the same age average about 20 percent less, or about 120 pounds. Some older bucks weigh 200 pounds or more when field dressed (about 250 pounds live weight) and the heaviest Nebraska whitetail on record was 287 pounds field dressed (about 355 pounds live weight).
http://www.holoweb.com/cannon/whitetai.htm
I saw a semi hit a deer the other day, broad daylight, those animals are so stupid when it comes to roads and vehicles.
That deer looked pretty thin when it ripped like an old sail in the wind. There had to be tons of blood and hair on the bike.