According to the old American song, the old gray mare, she ain’t what she used to be. But what about the old grey, bay or chesnut stallions? Is there any basis to the widespread belief that veteran stallions tend to become less effective once they are past their prime?

This is not an easy question to answer, partly because the picture is slightly different in the US, compared to Britain and Ireland. Perhaps because of the difference in climate (and the greater size of the American industry), Kentucky seems to have more long-lived stallions. Among the oldest active stallions in 2016 were the 23-year-olds Distorted Humor, Elusive Quality and Northern Afleet, who respectively covered books of 102, 55 and 106 mares.

Of the 22-year-olds, Awesome Again covered 71 and Tale Of The Cat 83, while the 20-year-old Lemon Drop Kid attracted 113 mares. There is also a sizeable group of popular American stallions which will be 20 in 2017, including Giant’s Causeway (48 mares), More Than Ready (132) and Tiznow (128).

Pivotal, who turned 24 on January 1, remains popular after another banner season

Pivotal, who turned 24 on January 1, remains popular after another banner season

The veterans’ brigade in Britain and Ireland has been depleted in recent years by the pensioning of such as Danehill Dancer, Cape Cross, Bahamian Bounty, Royal Applause, Zamindar and Peintre Celebre.

This effectively leaves Pivotal and Tagula, who respectively covered 81 and 49 mares at the age of 23 in 2016, and Dansili, who had a book of 79 at the age of 20. Rapidly heading in the same direction are Invincible Spirit, who dealt with 151 mares at the age of 19 in 2016, and Galileo, who was 18 in 2016, when his book stood at 158 mares.

I have always felt that the belief that elderly stallions become less effective with age is something of a self-fulfilling prophecy. Most stallions are only as good as the mares they receive and a stallion needs to be exceptional – a Mr Prospector, a Northern Dancer, a Danzig or a Sadler’s Wells – if he is to continue to attract top quality mares well into his twenties.

Breeders are less likely to risk their best mares with a stallion whose fertility may suddenly start to decline. The boredom factor mustn’t be underestimated, either, with commercial breeders and buyers both being constantly on the lookout for something new.

Increasing success at an earlier age can also contribute to the situation, as the accompanying hike in fee effectively forces many loyal supporters to start looking elsewhere, frequently to high-class young sons of the stallion concerned. A leading stallion’s decline can sometimes be traced to the time when he starts to face competition from his best sons.

By the time a stallion heads towards the age of 20, he is likely to be in competition not only with sons but also grandsons. His broodmare daughters will also be in full production, so his impact on the gene pool will be considerable, more so in Britain and Ireland than in the US. The end result is that a larger proportion of the best broodmares are unavailable to him, compared to the earlier stages of his career.

With stallion success being so much a numbers game these days, the perception that a stallion ain’t what he used to be may owe something to the inevitable reduction in the size of his book as he reaches veteran status.

Fortunately, the very best stallions tend to rise above such problems. Mr Prospector was as old as 26 when his Kentucky Derby winner Fusaichi Pegasus was conceived and 27 when he sired the champion sprinter Aldebaran. Northern Dancer was well into his twenties when the likes of Ajdal and Unfuwain were conceived. Danzig did even better, as he was 26 when Hard Spun and Astronomer Royal – the last of his many Group 1 winners – were conceived.

As I said earlier, American stallions tend to stay active that little bit longer than many of their European counterparts (though Hyperion was 27 when he sired Opaline II, the champion two-year-old of 1960). Sadler’s Wells had the extraordinary record of siring at least one Group 1 winner in each of his first 18 crops and he was 21 when he sired five Group 1 winners, headed by dual Oaks winner Alexandrova, Ask and Septimus, from a 2003 crop of 133.

I wish I could say that his last few crops proved equally effective but the truth is that his crops of 2004, 2006, 2007 and 2008 all drew a blank at the highest level. By then, of course, he was in direct competition with his excellent sons Montjeu, Galileo and High Chaparral.

So what does the future hold for Britain and Ireland’s elder statesmen?

The wonderful Pivotal will be 24 when he stands his 20th season at Cheveley Park Stud in 2017. Breeders are certainly keeping faith with him – and no wonder. He ranked as high as fifth on the leading sires’ table for 2016, thanks to a team featuring the Group winners Brando, Lightning Spear, Loving Things and Wings of Desire. His 2016 yearlings, conceived when he was 21, sold for up to 350,000gns.

His current level of his fee – it has been in the range of £45,000 or £40,000 since he turned 19 – has to be tempting when one considers that Pivotal was once the highest-priced British-based stallion, at £85,000.

His importance has been underlined by the emergence of his son Siyouni as one of the most sought-after stallions in Europe. Not to be overshadowed, Pivotal’s broodmare daughters have been doing so well that the son of Polar Falcon ranks third on 2016’s broodmare sires’ list. In finishing third, Pivotal was in extremely good company, as the top five positions were completed by Danehill Dancer, Danehill, Galileo and Sadler’s Wells who – collectively – have taken the title of champion sire in 26 of the last 27 years.

One of his daughters’ main attractions is that they have been working very well indeed with Galileo, with the juvenile fillies Rhododendron and Hydrangea being fine examples. It was one of Pivotal’s best daughters, Peeress, who produced a 1,300,000-guinea yearling to Galileo’s son Frankel. With his largely outcross pedigree, Pivotal looks set to keep on shining as a broodmare sire long after he has sired his last foal.

Dansili is three years younger, so there is no reason for thinking that he should slow down any time soon. But he too has been priced to reflect his advancing years, and breeders can now access him for £65,000, just two years after his fee was £100,000. It is important to remember that Dansili’s crop size – especially in recent years – has generally been a fair bit smaller than those of most other leading stallions.

He is credited with 1,272 foals in his first 13 crops – an average of 98 per crop – and two of his last four crops of racing age have numbered 77 foals. This excellent sire of fillies added another Group 1 winner to his collection when the three-year-old Queen’s Trust defeated the American defenders in the Breeders’ Cup Filly & Mare Turf in November.

Breeders are certainly keeping the faith with Pivotal, who ranked fifth on the 2016 sires’ table

With 77 members, Dansili’s 2016 crop of two-year-olds could be described as on the small side, but it contains quite a few lightly-raced winners with the potential to be smart in 2017. Among them are Titus and Talaayeb, who were both designated Rising Stars by Thoroughbred Daily News, and the other promising types include Tansholpan, Tempera, Shutter Speed and the Andre Fabre trio of Pharaonic, Franz Schubert and Trais Fluors.

The 2016 season saw five sons of Dansili represented by Group winners and the promise being shown by Zoffany bodes well for Flintshire, who has retired to Hill ‘n’ Dale Farm in Kentucky.

Invincible Spirit and Galileo, two others who will soon be classified as veterans, already face competition from a growing number of stallion sons. Fortunately their parentage provides plenty of hope that they still have a great deal to offer.

Invincible Spirit may be 20 years old in 2017 but his male line consists of Green Desert, Danzig and Northern Dancer. I have already mentioned how the last two continued to sire top winners into ripe old age and Green Desert’s last two Group winners, Maqaasid and Mazameer, were conceived when the Shadwell stalwart was 24 and 26 respectively.

Galileo’s career has already mirrored Sadler’s Wells’s in so many ways that it seems a safe bet – provided he stays healthy – that he will remain a major force for at least a few more years. By then, though, he could – like Sadler’s Wells before him – find his stallion sons snapping at his heels.