Hi.
Given the size of the animal, and therefore the size of the small intestinal track, not to mention the relative difficulty of preparing such a small track to be used as a string, I find that very hard to believe.
For a lute or a guitar, maybe, just maybe, but for a DB, a several hundered cats would be needed to be gutted for a single set of strings. The portion of the track that's traditionally used for the instrument strings was the leftover (too small) from the sausage making, so it was very cheap, cheaper than the sausage gut.
So, without a link to said article, I call cat strings in a DB BS.
Regards
Sam