Milk weed can be a problem as it grows quite densely where it established itself, and is not really grazed my any animals. Goats will eat the seed pods, and nibble on the leaves in winter, but it becomes problematic if it starts growing in any field that will be cut for hay. You don’t want as lot of weeds in your hay, as the weeds are generally wetter than the grass and may cause mould, and they may spread their seeds to other parts of the farm.
Fortunately when the ground is soft after rain, they can be pulled out quite easily. I am busy clearing a field of Smutsfinger grass that is being established. Once the grass covers the ground completely, the milk weed probably won’t grow again.
Cutting the weeds down doesn’t help though as the plant will just regrow from the cut stem. Pulling is the only way. Always lean down slope when you are pulling weeds and let gravity help you. Helps if you have a bit of counterweight in that region as well!