(Photo : The Virtual Form Guide)

A lack of diversity and dwindling numbers in the sire ranks have become clear trends in Australia - which is the world’s second largest producer of thoroughbreds behind the United States.

Owner & Breeder reports that Michael Ford, keeper of the Australian Stud Book, noted in a recent report that the number of stallions that covered mares has fallen 73% since 1988, from 2,917 to 768 in 2008. The number of mares bred has decreased by about 40%, falling from 44,413 to 26,800. Perhaps most remarkably, of the 768 stallions bred to in Australia last year, 114 were by Danehill and another 56 were grandsons of Danehill, with that prolific line thus accounting for 22% of the total stallion population.

And many of the Danehill line horses are some of Australia’s most active, with Coolmore’s young Danehill stallion Fastnet Rock the busiest in 2008 with a total of 248 mares covered.

Eleven of the top 20 sires in Australia in the most recent season are sons or grandsons of Danehill, including God’s Own, third most active stallion with 196 mares.

Others are Choisir (194), Holy Roman Emperor (180), Oratorio (173), Flying Spur (171), Not A Single Doubt (161), Stratum (159), Dylan Thomas (157), Commands (151) and Exceed And Excel (148).

Ford, however, focused his comments on shuttle stallions rather than the Danehill phenomenon. “Shuttle stallions have been the biggest influential factor in horse breeding in the last 20 years,” wrote Ford in a paper published by Australian Breeding & Racing. “In 1989 there were two: Bluebird and Last Tycoon, and they covered 163 mares between them. In 2006, there were 64, covering 5,627 (an average of 90 for each shuttle stallion) mares – more than one in five of the total Australian population.”