It's never happened before, and I've never tasted anything like this before in any raw milk, but one of our does gave some nasty tasting milk this morning.
It's hard to explain, but it almost tasted like barn... hayish, green, a little funk, but not goaty or sour.

The milking area is clean, the bucket and strainer are stainless and are always run through the dishwasher. She's always rubbed down then her teats and udder are washed before milking. The milk gets strained into a glass jar and put in the freezer for one hour before moving to the fridge.
Thoughts?
What would cause that? Every other drop of milk she has ever given has been sweet and perfect. Her supply has been increasing over the past week so that she's nearly doubled what she was giving us before, but the only change is that she's on her third or fourth week of Replamin Plus.
She gets free access to hay/alfalfa mix, grain at both milkings, BOSS, and free ranges on the front and back meadows.