I do a sheet(s) in Excel for each of mine. Usually get about a year and a half across one page.
Procedures/inoculations/tests down the Left Column, and Dates across the top, and just put an "X" in the proper cell. Also keep a Folder on each Animal with the hard copies of the receipts.
Real easy to make a CD of that, when you go on a Trip
CD would include Pictures, Ownership Documents, copies of other related materials.