There is an obscure grape variety called Cagnina:  I say obscure, because it only has one single holding institution, which has not even bothered to put in basic ampelographic information in this database, and which has no known synonyms. Cagnina di Romagna gives no hits in this database, so I don't think that Cagnina and Cagnina di Romagna are identical. It could be a designation rather than a grape variety.