What is a gelding?
In horse racing, a ‘gelding’ is male horse that has been castrated or, in other words, has had its testicles surgically removed, so that it is unable to reproduce and has no breeding value. Castration not only makes a male horse sterile, but typically inhibits stallion-like behaviour, making it easier to control and easier to train, especially around female horses. In Britain, the majority of male horses that participate in National Hunt racing have been gelded for this reason.
The castration procedure is typically performed on horses that are mature, skeletally, so that they reap the benefits of the hormone testosterone, which is produced by the testicles, on their physical development. However, the procedure is best performed soon rather than later – between the ages of six months and two years is typical – because castration at a late age may not eradicate aggressive, masculine behaviour that has been learned in the meantime.
Of the five ‘Classic’ races run in Britain – namely, the 2,000 Guineas, 1,000 Guineas, Derby, Oaks and St. Leger – the 1,000 Guineas and the Oaks are restricted to three-year-old thoroughbred fillies, but the other three are open to three-year-old thoroughbred colts and fillies. Nowadays, the Derby is rarely contested by fillies; the last filly to run in the race was Cape Verdi, trained by Saeed bin Suroor, who started favourite after winning the 1,000 Guineas in 1998, but could finish only ninth of the 15 runners. Nevertheless, since the Derby was inaugurated in 1780, a total of six fillies have won; the most recent of them was Fifinella who, in 1916, won a ‘substitute’ Derby run at Newmarket and, just for good measure, won the so-called ‘New Oaks’, over the same course and distance, two days later.