ATTRA, the National Sustainable Agriculture Information Service, has an excellent publication on this topic (https://attra.ncat.org/attra-pub/summaries/summary.php?pub=217).
Sericea lespedeza can be a good feed for goats and preliminary research indicates that it has deworming effects. However, it should be considered only as one component of a deworming program as it cannot be used to treat severely infested goats. Sericea as a feed will tend to lower fecal egg counts of parasites. Some goats may still get severe infections of parasites and will have to be treated with an effective dewormer.
Additionally, some states consider sericea lespedeza as a noxious weed and it should not be sown in those states.