Net price per liter after collection and quality deductions
Liters per cow per year (realistic average, not peak)
Total annual feed expense per cow (concentrate, silage, hay)
Veterinary, breeding, bedding, water, electricity per cow per year
Labor, machinery, land, buildings, insurance, loan payments (total per year)
At current prices, you need -- cows to cover all costs. Below this number, you're working for free.