I filter my milk into a one-half gallon canning jar as soon as I milk a doe, and then put the jar into a bucket of ice water up to the neck of the jar while I milk the next doe. Once I'm finished milking, I bring the bucket, with the jar of milk, back into the house and (here's the cool part) drop my little submersible fountain pump into the bucket. This circulates the water, and it cools the milk about twice as fast as without the pump. The pump cost around $10. The milk hits 42 degrees within half an hour of turning on the pump. Once the milk is cooled down, I put the jar into the fridge, turn off the pump, take it out of the bucket and hang it on a hook until next time. The pump is the kind you buy for personal fountains, available at craft stores. This cools the milk so fast, it's perilously close to Grade A!