Reclaiming Pasture & Removing Toxic Weeds

I have a horse and she’s a very important part of our family. But we have several toxic weeds destroying our grass areas.

The sandburs make it dangerous for all of us to walk out there and the chamber bitter is making my animals sick. If I don’t do something this spring, they will completely take over the entire property.

Is there anything I can do?

Any herbicides will end up getting into the garden via manure or compost, etc. not to mention all the other toxic effects.