With the exception of the opera Aida, Verdi did not set out to compose ballet music for his operas. But in order to get a performance of an opera in Paris in the 19th Century, a ballet section was de rigueur. So Verdi composed ballet music for those operas: Otello, Macbeth, Jerusalem (aka I Lombardi), Don Carlo, Il Trovatore, and I Vespri Siciliani, that were performed at the Paris Opera. These sometimes lengthy ballet scenes are rarely included in operatic performances today, though some of them, notably for Otello and I Vespri Siciliani, are sometimes heard as orchestral concert selections.
The short ballet episodes of Aida, on the other hand, were always intended by Verdi to be integral parts of the opera, are usually included in performance today, and are well-known to opera lovers.
Of course, the ballet music was intended to be the foundation for a visual show, so rhythmic regularity was all important. Much of the ballet music is repetitious and seems to be going nowhere, but without dancers on stage it's hard to know how appropriate this music was for its intended purpose. Perhaps the best of the ballet scenes are those of Otello, where the music is more dramatic and exciting than elsewhere. According to the included notes, Verdi took more than usual interest in adding these ballet scenes to the opera, and he sketched out the intended purpose of each scene. It appears that he would have liked them added to all performances of Otello.
For the most part, Verdi did not use music from the rest of the opera in his ballet scenes, but there are exceptions. The Don Carlo ballet includes a gorgeous chorale theme from the opera, and fans of Il Trovatore will recognize a brief reference to the "Anvil Chorus." The ballet score for I Vespri Siciliani is interesting in that it is almost 30 minutes long and consists of four individual ballets for each of the four seasons, starting with winter.
Not included in this compilation of ballet music is the very fine dance music in Act II, Scene 2 of La Traviata, which is an integral part of that opera. Verdi apparently had mixed feelings about including ballet music in his operas, and most of his La Scala performances did not include the ballet scenes.
Jose Serebrier and the Bournmouth Symphony Orchestra have now provided a 2 CD set of recordings of this ballet music for Verdi fans. As instrumental music, it is of variable quality and interest, as noted above. But Serebrier does an excellent job with the Bournmouth, and the sound quality is splendid. The included liner notes are very detailed and informative. Most of this music is also available in MP3 format. Recommended for those who want to have Verdi's instrumental as well as sung music.