Whether putting food in the refrigerator, the freezer, or the cupboard, you have plenty of opportunities to prevent foodborne illnesses. One of the basics of food safety is cooking food to its proper temperature.
I personaly always figured around 25lbs of hay per day for a average size cow when i was putting up hay. Alot of that of course they can get if pasture is available/accessable. Multiply that by your number of cows x average days you actually have to feed.
A: Cows will eat 2% of their body weight in hay per day in the winter. You can figure that you are going to need to feed hay around 150 days per year. If your cow weighs 1,200 pounds, she will need 24 pounds of good quality hay for 150 days. So a good starting point would be to have 3,600 pounds of hay per cow per year.