For 1973, Secretariat was again named Horse of the Year and also won Eclipse Awards as the American Champion Three-Year-Old Male Horse and the American Champion Male Turf Horse. When Secretariat first retired to Claiborne Farm, his sperm showed some signs of immaturity, so he was bred to three non-Thoroughbred mares in December 1973 to test his fertility. One of these, an Appaloosa named Leola, produced Secretariat's first foal in November 1974. Named First Secretary, the foal was a chestnut like his sire, but spotted like his dam. Secretariat's first official foal crop, arriving in 1975, consisted of 28 foals, the best of which was Dactylographer, who won the William Hill Futurity in October 1977. The first crop also included Canadian Bound, who at the 1976 Keeneland July sale was the first yearling to break the $1 million barrier, selling for $1.5 million. Canadian Bound, however, was a complete failure in racing, and for several years, the value of Secretariat's offspring declined considerably, especially given the rising popularity of Northern Dancer's offspring in the sales ring. Secretariat eventually sired a number of major stakes winners, including:  Ultimately, Secretariat officially sired 663 named foals, including 341 winners (51.4%) and 54 stakes winners (8.1%). There has been some criticism of Secretariat as a stallion, mainly because he did not produce male offspring of his own ability and did not leave a leading sire son behind, but his legacy is assured though the quality of his daughters, several of whom were excellent racers and even more of whom were excellent producers. In 1992, Secretariat was the leading broodmare sire in North America. Overall, Secretariat's daughters produced 24 Grade/Group 1 winners. As a broodmare sire, Secretariat's most notable progeny were:  Through Weekend Surprise and Terlingua alone, Secretariat appears in the pedigree of numerous champions. Weekend Surprises's son A.P. Indy was the leading sire in North America in 2003 and 2006, and is the sire of 2003 Horse of the Year Mineshaft and 2007 Belmont Stakes winner Rags to Riches. He has also established a successful sire-line that leads to Kentucky Derby winners Orb and California Chrome. A.P. Indy's leading sire-line descendant is Tapit, who led the sire list in 2014–2015 and is the sire of Belmont Stakes winners Tonalist and Creator.