Started or ustarted dams, does it matter?

Does it matter for the foal if the mother has started or what kind of career she had? The opinions are many but the facts are usually absent. To try to get a more scientific, fact-based understanding of the issue I have chosen to analyze all Swedish trotter born between 1990 and 2005, a total of 16 whole crops, and analyzed these with pedigree program Sophia. For those who do not bother to read the entire article I refer only to the table at the bottom.
There were born 74501 horses between 1990 and 2005 in Sweden. The best (measured by earnings) include Victory Tilly, Commander Crowe, Gidde and Torvald Palema, Zoogin, Maharajah, Revenue and Giant Diablo. A few are still racing but most have finished racing career and the numbers will not change much next year anyway.
Of the 74,501 horses 48,434, or 65.01%, had started in at least one official race. In total, these earned 9,850,642,367 SEK in total for an average of 132 222 SEK per horse. However, an average is only an average, and none of the 74501 horses have actually earned exactly 132 222 SEK!

Of the 74,501 horses a total of 19306 had an unstarted dam (no starts in official races, but could have gone a qualifier). Of these foals, 11180, i.e. 57.91%, have started at least one race. These have a total earned 2,124,048,911 SEK, an average of 110 020 SEK per horse.
This means that if the mother is unstarted then the starting percentage of foals are 7.10 percentage points lower than the average for all horses born 1990-2005. Earnings are 22 202 SEK lower, ie the earnings are 16.79% lower than the average.
It is difficult to further analyze this group but a little more research can be done. Some unstarted dams were actually talented young fillies who were injured early and covered immediately. Other unstarted fillies were racehorses with little or limited talent who failed to start despite the fact that they were given much time to learn the art.
We can try to separate by looking at when the unstarted dams had their first foal. So how are the numbers when the foal whose dams were unstarted did not get their first foal until they were 5 years or later? Of the 19306 foals with unstarted dams, it turns out that 13,976 foals have dams who did not get their first foal until she was at least 5 years old. Of these 13,976 horses "only" 7685 horses, or 54.99%, started - clearly the weakest starting percentage of all groups. These foals have earned 1,278,866,854 in total, which amounts to an average of only 91 504 SEK per horse. So earnings for this group is the 40 718 SEK below the average, or 30.80% lower than the average!
So how did dams who were bred early do? They were 5330 horses with such a dam. These have a starting percentage of 65.57% and average earnings of 158 570 SEK. It is very interesting to note that this is above average! But it is also worth noting that this is an extremely diverse group. In this group of 5330 horses you find Commander Crowe (whose dam Somack got her first foal when she was 3 years), Huxtable Hornline (dam Hi Crown had her first foal when she was 4 years), Lovely Godiva (whose dam Keystone Gwen got her first foal when she was 4 years) and Elitlopp winner From Above (his dam A Gift From Heaven got her first foal, Eternal, when she was 4 years and From Above was born the following year).

Of the 74,501 horses the remaining 55,195 horses had a mother who had started at least one official race. Of these 55 195 foals, 37,254 of these, or 67.50%, had started in at least one race themselves. They have earned a total of 7,726,593,456 SEK, or 139 987 SEK per horse. This is an starting percentage that is slightly above average and the average earnings are also approximately 5.5% above average. The difference from unstarted mothers are noticable.
But what about the rest? Is it possible to see some trends if one looks at the career of the dams? If I diver into the the numbers some interesting patterns emerge:
20104 horses have mothers who have earned more than 0.1 million (100,000) SEK. Of these 14,888, or 74.05%, have started, and this group has earned a total of 4,081,803,197 SEK, or an average of 203 034 SEK per horse. This is interesting, because you can already see here that the starting percentage and average earnings are considerably higher. So already I can draw the conclusion that it is not enough that the mother has started, she should have shown some ability as well.
What happens if we increase the requirements for mother's own earnings and analyze the group of horses with a dam who has earned a minimum of 0.25 million (250,000) SEK? It turns out there are 8276 such horses in the group. Of these 6402, or 77.36%, have started, and these have earned 2,103,994,943 SEK, or an average of 254 228 SEK per horse. We see that starting percentage is even higher and average earnings are over twice as large as if the mother is unstarted!
If I double the requirement and only look at foals where the mother has earned at least 0,5 million SEK I find 3513 horses. Of these 2779, or 79.11%, have started, and these have earned a total of 1,123,320,310 SEK, or an average of 319 761 SEK per horse.
A common belief is that the best race mares do not make very good broodmares. So far, statistics show that better race mares do indeed make better broodmares. What happens when one looks at the offspring of mares who have earned at least a million? There are 1,211 horses born 1990-2005 whose dams are millionaires (in SEK). Of these, 956, or 78.94%, have started, and these have earned 503 099 443 SEK, or an average of 415 441 SEK per horse. It's almost scary how average earnings have increased by almost 100 000 SEK!
And what about the horses that has dams who have earned over 2.5 million SEK each? There are 241 such horses have mothers who have earned over 2.5 million SEK. Of these, 193, or 80.08%, started and these have earned 102 424 047, ie 424 996 SEK per horse. Of only 241 horses then 23, all 9.54%, millionaires! If you believed that good race horses do not make good broodmares you should really think about this again! On this list you find horses such as Kramer Boy, Smashing Victory, The Bad Boy, Mr. Jägermeister, Express Lavec, Staro Cold Carat, King Lavec, Vanessa du Ling, Paul November and Easy Lover.
Category Horses Starters Start% Average earnings
All horses 74 501 48 434 65.01 % 132 222 SEK
Unstarted, first foal at 5 or later 13 976 7 685 54.99 % 91 504 SEK
Unstarted, first foal at 2, 3 or 4 5 330 3 495 65.57 % 158 570 SEK
Started, any earnings 55 195 37 254 67.50 % 139 987 SEK
Started, earnings > 100k SEK 20 104 14 888 74.05 % 203 034 SEK
Started, earnings > 250k SEK 8 276 6 402 77.36 % 254 228 SEK
Started, earnings > 500k SEK 3 513 2 779 79.11 % 319 761 SEK
Started, earnings > 1M SEK 1 211 956 78.94 % 415 441 SEK
Started, earnings > 2.5M SEK 241 193 80.08 % 424 996 SEK

The conclusion is both easy and brutal. The better the performance of the dam, the higher the expected starting percentage and expected earnings of her foals. Breeding unstarted broodmares can be a risky venture, especially if she was bred late and, I will venture to guess, was unstarted because she showed a lack of talent. The statistics show a small exception when the unstarted broodmare mother was bred early, so the key question is probably why the mother was unstarted. It is not possible to go deeper in this group based on the statistics alone, but there is every reason to believe that if the mare showed talent but was injured and therefore bred early, that is something completely different than if the mother lacked a talented for trotting altogether.

So what does this really mean for unstarted broodmares? Unfortunately I know that many people will misinterpret what I am saying and claim that I say that you should never breed on unstarted broodmares. I am saying no such thing! What I am saying is that unstarted broodmares can produce well but started broodmares with some performances on the track produce better on average. So there is a bigger risk involved when using unstarted broodmares but they key question, if my assumption above is correct, is why the broodmare is unstarted. An unstarted broodmare can be unstarted for a variety of reasons. If she is unstarted because she showed absolutely no talent it follows that she has very little quality to pass on to her foals. If she showed big talent but got injured it is reasonable to expect that she will produce as if she had a good or great career. If she was unstarted because she was never put in training then there is no indication how she will produce from this perspective. Her pedigree, her maternal family and her siblings can be expected to give some clues but it is very important to be extremely realistic.

And as always, statistics show general trends. Exceptions exist but they are just that - exceptions. The general rule is very clear. Better race mares make better broodmares while unstarted onces are a riskier proposition.

Marloes Harkema is the manager of Sophia Pedigrees and a pedigree researcher/analyst. She can be contacted at