When it comes to goats.
1) Identify where parasite loads can be high. For example wet or moist hot summer grazing lands could be a issue.
2) There is
alot of advice on worming goats but much of it untested. Verify with several sources before trying anything new. Try on just one goat first.
3) Check out minerals, I remember moose dying from lack of Cobol in diet. Well goats are browsers and eat more than just grass. May have to supplement what you cannot provide with grazing.
4) For some reason the studies I find that seem to show impact on parasite seem to be linked to tanins in the plants.
5) Not all animals have same reaction to parasites. Some people practice removal of animals with high parasite loads.
6) Consider chop and drop
trees so you can provide alternative
feed during times of high parasite activity.
7) Rotate grazing areas to reduce parasite load.

Determine parasite life cycle and use
chickens, etc to disrupt the parasite life cycle in your grazing areas.