Inventory Tracking

We have a feed mill and need a spreadsheet to track bulk ingredients that go into feed rations. We have several bulk ingredients that are use to make different mixes each mix uses a so much of each ingredient, I have put all of the mixes in a spreadsheet with the amounts of bulk ingredients used in each mix. I need the spreadsheet to track my inventory daily with me entering the amount of the mixes produced each day. I can make it take out of the bulk but have to reenter the starting amounts each day. I want it to keep track of my ingredients with out reentering the starting amount everyday.