I have a spread sheet. the columns are: sex, ear tag number, brand (we run 3), birth date, brand date, brief description (color, horns, etc), vaccinations, mother, calves, date last seen, random notes. don't have a scale so I don't do weights. I also try to have photos of everything (in another file, haven't figured out how to merge without crashing my computer) I keep a matching spreadsheet of animals that are gone (sold, dead, not seen in a year or more) I move (cut and paste) the lines to it when something is sold or whatever and can add the date, weights, $$$ etc there.