For the computer records, I use Ranch Manager, there is a Canadian and a USA edition. If you're interested, you can find it here at
http://www.lionedge.com . Keeps as much info as I want it to and, more, it is easy to use, they update regularly, and their customer service is super too.
But, I also keep very detailed paper records. I have templates of them all on my computer, and I print them out as I need them. I like the paper records for a # of reasons. I will always have the info, even if the computer crashes and I didn't back up stuff. And, I find I remember stuff better when I write it down instead of just using the computer.
I have an individual record for each cow, that keeps her info (Bday, BW, WW, Desc, Dam, Sire etc) and info on every calf (B-day, BW, WW, Desc, sire, Tag info etc)
Calving report, which keeps Tag, B-day, Desc of cow and calf, BW, info on calving and calf vigor and a comments section.
Breeding Report
Medication Report
Bulls used report
Growth report
I have copies of them all in Adobe. If anyone wants to see, just email me and I can send them to you. They are all setup for a commercial herd, but could easily be setup for a purebred herd, I imagine.