I found this article on the kind of mastitis that Onyx has.
It was the clearest, most concise information I've found. It looks like the treatment we gave last week may have actually made things worse by releasing toxins.
In other news, the contractor scheduled to erect our barn today has not returned calls from my husband in two days.
Good news, we've heard from the contractor and he's coming Monday. Our barn is going to be like the picture above. Jeff is a good carpenter and is going to build in a loft, sides and stalls for the animals.