I have a wonderful Vet that has written me one heck of a VFD.  They wrote it up early in the VFD days and it hasn't changed yet.  I renew it every 6 months (HOLY CRAP it's due next week!) and I just go buy what I need.  This winter has been mild which here means wet instead of frozen.  Lots of coughing, snotty noses, etc.  I've been thinking of buying Aureo 10g by the pallet.

I use Sulfa boluses rather than water soluble.  There's no way for critters to alter their intake if you jam it down their throat.