One of the reasons this is not recommended for human use, is the FDA or USDA,
whichever controls this, has different guidelines obviously for products used
for humans vs animals.  This includes the level of cleanliness used to
process product, purity of product, etc.i.e. an animal product, since it is
used in a barnyard etc, might be allowed to have a few dead bugs, hairs, etc
per batch that obviously would not be allowed in a human pharmaceutical.
Don't mean to gross anyone out, but since tomato sauce manufacturers for
example are allowed to have a certain level of mold before the product is
declared non-edible, I really wouldn't want to think about what's ok in vet
products.
So what I've told folks who ask about BB is just this:  that it is a product
designed specifically for animals, and not intended for internal use, and
since one of the reasons we breastfeed is to provide our baby the best food,
that we have some measure of quality control over, and the manufacturer
dosen't recommend this for human use, then I obviously can't recommend it.
 Then I go into my song & dance about how we do heal sore nipples, correct
positioning, etc, and there is a product that is the main ingredient in BB
but in a highly purified form, etc.

Kathe Catone, IBCLC, LLLL ([log in to unmask])