Don't worry about opportunity costs, the value of your labor, land depreciation, etc. That stuff is all well and good; but the numbers you need to stay on top of probably with a daily ledger (preferably computerized) are the production costs of your cattle operation. You or your accountant will absolutely need this information (save all the receipts) at the end of the year to do your taxes.
If you have never filled one out before I like to have one page (my spreadsheets let me have multiple pages per file) titled Cash Costs.
A list of cash costs would include:
purchased feed
purchased hay
hired labor (if you paid your cousins $50 to help run up cows record that as "day labor")
diesal used in the cattle operation
fertilizer used on pastures and hay fields (if you bundle the hay and cattle enterprises together)
vaccines
minerals
hauling
ear tags
insecticides,
advertising,
herbicides,
wire and posts (used in fence REPAIRS),
repairs on equipment used in the cattle biz,
repairs on barns and buildings used in the cattle biz,
utilities (hopefully the barn's have their own power meter),
professional associations (like Cattleman's Assn, Angus Assn., Farmer's Federation.....do NOT deduct any contributions to industry PACs),
veterinary costs,
property taxes (do not deduct the house property taxes as a business expense....on a small operation the accountant MAY put all the property taxes on the schedule A rather than the schedule F....you pay him too figure out which way to go with that)
and miscellaneous (everything I forgot).
You also want to fill out form 4562 Part V to calculate the mileage you put on your vehicles as part of your ranch business. Keeping a log in your truck is the only way to be accurate. A large ranch has business and personal vehicles and the two never mix roles; but most of us never get quite that big. A truck that does ONLY ranch business you might want to treat as farm equipment and depreciate and deduct ALL the expenses.
You should have a second page listing all the equipment you have purchased, the farm buildings contructed, the wire and the posts you bought for fence CONSTRUCTION, and all the breeding stock you have purchased. You need the date purchased and the purchase price. When you dispose of it you need to record the disposal date (for livestock that could be the date of death). You need this information for you and your accountant to fill out the rest of Form 4562 and calculate your deducatable depreciation expense which also goes on Schedule F.
Total expenses includes all the cash costs, the depreciation expense, AND the interest expense you pay on money borrowed (for land, operating loans, equipment, and business trucks)