I keep pretty in depth records on performance. I have a good cow program, and I love Excel. Health records are mostly kept just so I know what, why and when the withdrawal is, the only time they ever really get looked at again, is to make sure that we aren't retreating something to soon, or to decide that we need to try another treatment for something sick. I've never payed to have someone analyze my records, but I do that my self. And I really find that I like my records when I am trying to convince DH that a certain cow should be culled, especially if it is a good looking cow...lol
I keep an individual page on every cow. Mostly this just covers her calves and their performance, and basic info about her. I keep track of Birthdate, BW, Sex, Description, Assist, horned/polled, sire, wean date, WW and ADG as well as space for comments. This is probably the most used part of my records. I will cull off of this record. I've picked up on cows that have a higher than expected # of malpresentated calves, poorer performing calves, poorer health calves, high BW calves. I will use this when trying to decide whether to keep or cull an old cow, using BW and WW especially.
Then, I have a spreadsheet where I evaluate the performance of bulls calves. I enter each calf and then average the BW, Assists, WW, ADG and 205 day weights. Of course this is only possible if you know who the sires are. This has been pretty useful when deciding what cows to breed to what bull, or if a bull is throwing exceptionally high or small BW or WW calves. I have some cows that I know have a tendancy to have high BW calves, so I don't want to breed them to the highest BW bulls we are using.
I also use Excel to keep track of calving to breeding to calving for each cow.
The cow program (Ranch Manager) I like because it puts the vast majority of my info into 1 place. I can look up a pedigree, the # of calves, their BW's, treated cattle, what cattle are in what pastures, with what bulls etc all in one place. I use it a lot to sort by breed or colour or age. I wish it was more performance orientated, but they are working on that.