Green Dancer, a top European and North American stallion who had recently been pensioned, was euthanized Friday at Graham J. Beck's Gainesway Farm near Lexington, Ky. The horse was 28."Green Dancer's condition deteriorated rapidly this past week and he was humanely destroyed," said Gainesway's Michael Hernon.The son of Nijinsky II who sired 83 stakes winners had been pensioned last week because of the infirmities of age. Green Dancer, who was produced from the Val de Loir mare Green Valley, won the Observer Gold Cup (Eng-I) as a 2-year-old and also took the Prix Lupin (Fr-I) the following year. He won the classic French Two Thousand Guineas (Fr-I) in 1975 and a son, champion Green Tune, won that race in 1994. Green Dancer's other stakes winners included Prix de l'Arc de Triomphe (Fr-I) and champion Suave Dancer, plus Greinton, winner of the Hollywood Gold Cup (gr. I).Green Dancer was also a prominent broodmare sire, with Sandpit, Peaks and Valleys, and Halling among the 94 stakes winners produced from his daughters.Other advanced age stallions living in pension at Gainesway are Lyphard (31 years old), Big Spruce (31), and Stop the Music (30).