I don't think 4K per head would be outrageous. 5K would be getting there. That's considering they are average, run-of-the-mill cows. Replacement including cost of replacement. And the missing, damaged, dead calves or any that you can sell/raise and the costs of that end would have to be figured differently... but with the price of weaned calves it might hit close to what the cows are worth.
@CowboyRam I don't remember you mentioning if there were any calves left orphaned or whether the total number included calves that left a mother cow without.