Well lots of people have read this and no-one answered so I'll start you off then others will no doubt wade in with other opinions. Fluke or worms, different things and different treatments.
First -all the things everyone says as standard.
Speak to your vet.
Search on here for old posts, lots in this and the sheep section.
Look at the NADIS and SCOPS websites.
Do FEC and ask for them to check for fluke as well though it doesn't show early stage.
The withdrawal on flukicides was changed a few years ago to say never use in milking animals.
When I asked the vet what dairy farmers used he shrugged said they use it anyway and don't tell anyone or their cows don't go out. None of which sounded right.
Is your ground likely to harbour fluke.
In theory goats being browsers should be less likely to pick it up.
If you're going to use something use it well before you start taking milk for the house.