If she has enough milk, milk out some colostrum to freeze. Then you will have some when problems arise. If you do that with as many girls as possible, you can end up with a good amount in your freezer.
I put mine in plastic baby bottle inserts. I put about 4 ounces in each one and then seal them up with tape. I freeze them upright and then place the frozen ones in gallon freezer bags. Mark the date on each one. It is good for a year.