Comparing Sire Lines at the Highest Level

Comparing Sire Lines at the Highest Level

There is interest in comparing sire lines at the highest level in racing jurisdictions around the world. I have just completed an exercise for an American client in evaluating the sire lines in last week’s Kentucky Derby. Some of the world’s current leading sires are surprisingly absent.. To look at the issue further I decided to compare the top sires in America with those in Australia. I have not used the usual tools (average, earnings, winners per runner, stake earnings etc).

Keeping it very simple I have measured how many times a sire occurs in the pedigree. as the basis for this comparison. The data I have used comes from  two important races for 3yo as they are the top of the crop at the time they raced. The results will perhaps show what was important to breeders four years ago and perhaps also today. I have used the standard 5 generation pedigree (30 horses,15 on Sires side, 15 on the Dam’s side). The examination was not to find all the sire/broodmare lines, but look at which horses are contributing most to the pedigrees of the combined field. One can of course extrapolate from there.

Comparison of Sires in Kentucky Derby 2020 and Caulfield Guineas 2019.

I have chosen to compare the current sires whose progeny make up the fields in these two races. Both races are G1 races for horses of three years, of similar distance, worth approximately the same stake money. Exceptional winners of both races usually go on to be successful sires. They are also Races that owners would love to win.

Seattle Slew: a true champion in every way

The Kentucky Derby commenced in 1875.  In the last 50 years or so Secretariat (1973), Seattle Slew (1977), Sunday Silence (1989) and Unbridled (1990) have gone onto great things.

A P Indy: a son of Seattle Slew with 63 active sons at stud

The Caulfield Guineas commenced in 1881. It has also unearthed a string of talent. Luskin Star (1977), Redoute’s Choice (1999) Lohnro (2001), and Starspangledbanner (2009).

To have a position on the list a Sire has to be mentioned at least three times. The results are tabulated below:

What is interesting in the data?

Firstly, the stalwarts Mr Prospector and Northern Dancer maintain their powerful influence in both Countries.

  • The low showing of Danzig in America compared with Australia is surprising. No Danehill blood in the Derby begs many questions. One wouldn’t think quality would be one of those. Danehill was the broodmare sire of Frankel, considered by some (not by me) to be the world’s best horse ever. Danehill currently rates 83rd in Northern Hemisphere’s broodmare sire list. Perhaps there is something in that.
  • The Champions, Seattle Slew and A P Indy are well represented in the Derby but are noted to be largely absent in the Guineas.
  • The same could be said for Storm Bird and his son Storm Cat. The Storm Cat line is going well in America. Into Mischief, a great grandson of Storm Cat was America’s most sought-after sire in 2020. Storm Cat  has 92 active sons at stud.

Genetic Diversity

Horses in today’s thoroughbred population can trace their paternal linage to just three stallions. Similarly, more than 70% of thoroughbreds can trace their maternal linage to just 10 mares. Thus, there is little genetic diversity. Incorporation of the genes from some of the outstanding sires could provide that small change which separate success from failure in the breeding business.



About Dr Bob Jemison

Starting Early

I loved going to the race track from an early age but my thoughts never focused on becoming a breeder and owner. My grandfather Percy Duncan took me to Cheltenham Racecourse in South Australia. He frequented the course quite often. He had quite a thing for Victorian riders and horses-“They don’t come here for nothing” was his favourite saying.  

Dr Bob

The Christmas Handicap was held on Boxing Day and the Port Adelaide Cup was on the 28th A  public holiday in South Australia. My earliest memory of those events was Cellarman winning the Port Cup. I was 5 at the time and this was the first of many Christmas Carnivals he took me to. I was also there in 1961 when Tulloch won the S J Pullman Stakes to become the first horse in Australia to pass the 100,000 pounds ($2000,000) stake earnings mark. To get there I and my friend Jim Miers had to walk from home. We crossed the railway tracks at the back of Holden’s factory. Next  under the fence at the 5 furlong barrier start. It was then a walk to the straight to the 9f 69 yard start. To see such a Champion, it was worth the time.

When the Government were set to sell the racetrack, I wrote a Letter to the SA Government pleading for them to reconsider and John Letts gave a passionate speech at a public meeting at the Woodville Town Hall in support. But all to no avail –unless it is election time governments have no inclination to listen to the wishes of the public.

Why I Love Oakbank

Nishiazabu-A nomination for Hose of the Year 2016

Grandpa also had great affection for the Easter meetings at Oakbank racecourse. He once owned the Great Eastern Hotel at Littlehampton which was the closest pub to the track. Unfortunately the Great Depression wiped him out but his love for Oakbank remained.  The first winner I remember was Royal Pentzia. I have a vague recollection that this horse started in a Melbourne Cup and went out with a huge lead before stopping to a gentle trot –but I might be mistaken.

 Later it was a great thrill for me as a breeder and part owner of Nishiazabu who had three starts in the race. However, the best he could do was a second. But he got a nomination for Horse of the Year in 2016.

Racing Around The World

I maintained my interest in racing when I studied in England and attended a number of great races. Ribero in the St Leger at Doncaster in 1968, and Highland Wedding in the Grand National at Liverpool in 1969. I met up with Steve Roman, a fellow organic chemist, and he told me of his interest in horses.  This is set out in his excellent book DOSAGE Pedigree and Performance published in 2002. In 1970 I returned to Australia armed with a BSc in Biochemistry and Honours, and a PhD in Organic Chemistry and joined a Chemical Company. At one point I ended up running an animal health business!


At Hollywood Park with Julie Krone and Gary Stevens, two of the greatest jockeys that  ever lived

Race Club Administration and Travel 

I moved to Ballina on retirement and did a lot of travel. I was able to attend  some exciting race meetings overseas and met some wonderful people. Two Kentucky Derbies, the last Hollywood Gold Cup, Irish Derby, Chester Cup and visits to Singapore racing were all wonderful times.

There came an offer to join the Board of the Ballina Jockey Club and I was only pleased to accept. After seven years, two as Chairman, I was sacked with the rest of the Directors when the Club ran out of money. The financial problem was due to the Club’s inability to race on more than 50% of its meetings. Wet tracks meant no racing and no income.  All the time I was a Board member and many years prior, the NSW racing authorities were always promising to upgrade the track.  A new track, especially a Strath-Ayr surface would mean the Club could race on 100% of programmed race days not 50%. It was inevitable that with little income at some point the Club would no longer be able to continue operating. The Directors might have gone but the track has not been renovated and meetings are still abandoned..

Before I became a breeder owner, in 2000 I partnered with others to buy and race horses. My initial steps were only moderately successful. Some did win races but were not up to city standard and they were far from self-supporting. There is enjoyment in racing horses as a member of a team (syndicate) and the social interaction is rewarding. However, as I learned more about pedigrees and racing, and the role of a breeder and owner, the more it seemed to make sense to breed and race my own. I have had a winner in every Australian State except Western Australia.