most of the raw materials are out of china.
UG labs will be quality control levels will vary considerably, there is no real hard answer.
though legitimate Veterinary products are produced under the same or relatively the same conditions as pharma products, at least in the US.
Most Vet products used to, and to some extent still do, come out of mexico where conditions and restrictions are not quite so stringent. You will find some UG labs produce much cleaner and accurately dosed products (if this is what you are comparing too), of course you will find some of the dirtiest "bath-tub" type products as well. Ones loaded with BA/BB to keep them "clean".