What age do stallions start their breeding careers?
The perception is that Australia’s best young colts more than ever are being rushed off to stud, but do the statistics bear this out? By The Numbers investigates.
Of the 17 new Australian-bred additions to Australian stallion rosters in 2023, just four were beginning their breeding careers at four years of age.
It’s a number which seems surprising in the context of the perception that our best and brightest young colts are being quickly moved on to stud duties. In the case of the class of 2023, less than 25 per cent of new faces on stallion rosters were retired after their three-year-old seasons.
Two of those horses, Jacquinot (Rubick) and Daumier (Epaulette), are Group 1 winners. Daumier is the only Group-1 winning two-year-old colt of that crop, with the remaining top-level juvenile races taken out by fillies, which is perhaps why the number of four-year-old stud inductees this year is historically low.
In comparison, there were eight locally bred horses who entered stud this year at aged five, a list headed by Anamoe (Street Boss) and including fellow Group 1 winners In The Congo (Snitzel), Artorius (Flying Artie), Hitotsu (Maurice) and Paulele (Dawn Approach). Two stallions entered stud aged six, two aged seven and one aged eight. The average age of those 17 Australian-bred stallions is 5.29.
Arion lists 274 Australasian-bred stallions active at Australian studs in 2023 and the average age at which these stallions began their stud careers was 5.02. Of those 274 stallions, 37.6 per cent, or 103, retired to stud at four, 34.7 per cent (95) retired at five and 16.0 per cent (44) aged six.
So we can see that this year’s cohort, with comparative percentages of 23.5 per cent of new additions being four-year-olds and 47.1 per cent of five-year-olds, is not consistent with the longer-term trend.
The 2022 induction of 17 Australian/New Zealand-bred new stallions was more heavily influenced by four-year-olds, who made up eight, or 47.1 per cent of that total, while there were four five-year-olds (23.5 per cent) and four six-year-olds, plus a seven-year-old. The average age of those stallions was 4.88.
In 2021, 19 locally bred horses began their stud careers, with 11 of them, or 57.9 per cent, four-year-olds, while there were four (21.1 per cent) five-year-olds and two each of six and seven-year-olds. The average age of those hoses was 4.74.
The Covid-19-impacted 2020 season saw a bit of a boom in locally bred new additions to stallion rosters, with 32 new faces. Of those, 15, or 46.9 per cent, were four-year-olds at the time, while six were five-year-olds (18.8 per cent) and six six-year-olds. There were two each in the seven and eight-year-old categories, one who was nine and the average age was 5.16.
Going back through the crops we can see that the 2023 average age of the new inductees to stud is the highest it has been since 2014. It is interesting that, not dissimilar to the current crop, the 2014 crop of four-year-old stallions featured no Group 1-winning two-year-olds as those major races in 2013 had been won by either fillies or geldings.
Age of new stallions in Australia by year
| Year | Total | 4 | 5 | 6 | 7 | 8 | 9 | Ave age |
| 2023 | 17 | 4 | 8 | 2 | 2 | 1 | 0 | 5.29 |
| 2022 | 17 | 8 | 4 | 4 | 1 | 0 | 0 | 4.88 |
| 2021 | 19 | 11 | 4 | 2 | 2 | 0 | 0 | 4.74 |
| 2020 | 32 | 15 | 6 | 6 | 2 | 2 | 1 | 5.16 |
*Australasian-bred stallions only
When we filter the list of active Australian-based stallions by race performance or service fee, we see the average age drop and the proportion of those who began their careers as four-year-olds increases.
There are 99 locally bred stallions on Australian rosters who won Group 1 races in their careers. Of those, 44, or 44.4 per cent, retired to stud at four, while 33, or 33.3 per cent, retired at five. The average age that those Group 1-winning stallions retired to stud was 4.90.
When you only include those stallions who have a 2023 service fee of $10,000 or more, we see an even greater shift towards those who retired from the track immediately after their three-year-old seasons.
Sixty of the 99 active stallions in that category, or 60.6 per cent, entered stud at four, while a further 23 began their breeding careers at five. That means of the 99 most commercial locally bred sires in Australia, 83.8 per cent retired from the track by the end of their four-year-old season. Their average age is 4.63.
The average age for going to stud for those Australasian-bred stallions who featured in the top 100 on the sires table last season was around the same mark, 4.65, with 39 of that 74, or 52.7 per cent having begun their breeding careers at age four.
Overall, 82.4 per cent of that list had entered stud by age five, but interestingly, not the two stallions who topped the table. I Am Invincible (Invincible Spirit) and So You Think (High Chaparral) began their breeding careers in Australia when aged six.
The average starting age of the 62 Australasian-bred stallions on New Zealand rosters in 2023 was 5.38, substantially higher than the Australian figure of 5.02. Of those 62 horses, just 11, 17.7 per cent, started their stud career at age four or younger, while 30 (48.4 per cent) started at five. That means 66.1 per cent in New Zealand had begun their work in the stallion shed by five years old, compared to 72.3 per cent in Australia.
Starting breeding age of active stallions in Australia
| Category | Total | 3 | 4 | 5 | 6 | 7 | 8 | 9 |
| All stallions | 274 | 1.1% | 37.6% | 34.7% | 16.0% | 6.9% | 2.6% | 1.1% |
| Group 1 winners | 99 | 0.0% | 44.4% | 33.3% | 11.1% | 9.1% | 2.0% | 0.0% |
| $10,000-plus service fee | 99 | 0.0% | 60.6% | 23.2% | 9.1% | 6.1% | 1.0% | 0.0% |
| Top 100 in 22-23 sires table | 74 | 1.4% | 52.7% | 28.4% | 14.9% | 2.7% | 0.0% | 0.0% |
*Australasian-bred stallions only
Stretching the geography further to look at the United States and we see that the average age that active northern hemisphere-bred stallions in that country went to stud was higher again at 5.6. Of those 417 active stallions, just 80, or 19.2 per cent, retired to begin their careers at four, while a further 142, or 34.1 per cent, started breeding at five. Adding in a handful of ‘three-year-old stallions’, we have 55.2 per cent beginning their stud careers by age five.
Those statistics are a bit different when we look at only those American stallions who won Grade/Group 1 races. There, we see 68 of 89, or 76.4 per cent, having begun at five or earlier.
In Great Britain, the average starting age for the active stallion population (NH-bred) in 2023 was 5.67, with 62 of the 125 stallions, or just under 50 per cent, starting out by age five. Just 27, or 21.6 per cent had begun their careers at the age of four or three.
Again, filtering by stallions who went to stud as Group 1 winners, we see a much higher proportion – 39 of 65, or 60 per cent – of stallions began breeding at five or younger.
In Ireland, the average starting age of active stallions was slightly lower at 5.42, with 112 of 209, or 53.6 per cent, having begun stud duties by five years of age. Of those, 27.7 per cent (58), had begun their stud careers by age four, higher than any other country above, except for Australia.
Filtering by Group 1 winners, we see 61 of 103 Irish-based Group 1-winning sires, or 59.2 per cent, had begun duties by age five, while 34 per cent had started by four.
Japan’s system for proving its stallions is far more rigorous than elsewhere in the world and, as a result, the average age the active list of active stallions began their career is much higher at 6.76. Just 58 of 238 listed stallions, 24.4 per cent, began their careers at five years of age or younger, while only 25 of those, 10.5 per cent of the total, began at age four or younger.
There are 132 stallions in Japan who won at the elite-level on the track and 29.5 per cent of those began their careers aged five or younger, while only 12.1 per cent started at four or younger. The corresponding figures in Australia are 77.7 per cent and 44.4 per cent.
Percentage breakdown of age active stallions went to stud around the world
| Country | Total | 3 | 4 | 5 | 6 | 7 | 8 | 9 or older | Ave age |
| Australia | 274 | 1.1% | 37.6% | 34.7% | 16.0% | 6.9% | 2.6% | 1.1% | 5.02 |
| New Zealand | 62 | 1.6% | 16.1% | 48.4% | 21.0% | 6.5% | 4.8% | 1.6% | 5.39 |
| United States | 417 | 1.9% | 19.2% | 34.1% | 20.9% | 14.4% | 6.2% | 3.4% | 5.59 |
| Great Britain | 125 | 0.8% | 20.8% | 28.0% | 26.4% | 12.0% | 10.4% | 1.6% | 5.67 |
| Ireland | 209 | 5.7% | 22.0% | 25.8% | 27.3% | 10.5% | 7.2% | 1.4% | 5.42 |
| Japan | 238 | 0.8% | 9.7% | 13.9% | 22.3% | 19.7% | 16.0% | 17.6% | 6.76 |
* Restricted to stallions bred in the same hemisphere