Breeding records, show records, feeding records if anyone needs to take over, delouse record, tattoo & castration records, blood test records, things like that. For the milk records also write down how much they milk, so you can track fluctuations, or any abnormalities.
All those records are useful to have, and you're not going overboard by keeping them. Some day in the future you will almost certainly thank yourself, when you need to know something and you'll have the information there. Oh, more records (not charts) include money spent, on what, where, and when; and money made, on what, from whom, and when.