This survey was made using my database (extensive but no way complete) and considered foals born between 1998 to 2001 inclusive.

The sample size is 40593. The number of these with one or more RF's is 3809. This suggests that just under 9.4% foals incorporate mating to superior females.  This result is rather surprising because the last time I looked 5 or 6 years ago this it was about 5%. I think that early 90's in particular this way of inbreeding was made more popular and the rise could be because of that. Another explanation for the rise in popularity might be the sources through which the superior mares are found are popular.

Next stage was to look at those 3809. Of these I have thrown out those mares that appear in less than 5 pedigrees.

Here's the top 5.

These 5 account for over 60% of the RF's inbreedings found. The other thing that is pretty clear is that they are also found through the very strongest contempary stallions.

One thing that I should state here that there has been some double counting. Most foals had just one mare being inbred to but 259 had two and a handful had more. The vast majority of the 259 matings with more than one RF's nearly all involved Almahmoud behind Natalma or alongside others.  I counted these twice.

As an aside those 259 with more than one RF had a few successes. Namely:

Group 1 winners
ASHADO = Cosmah & Almahmoud
DENEBOLA = Natalma & Almahmoud
STORMING HOME = Natalma & Almahmoud
AL MAHER = Natalma & Almahmoud
SOUND ACTION = Natalma & Flaming Page
POMP AND GLORY = Love Game & Knight's Daughter
JOHAR = Mixed Marriage & Somethingroyal

Group 2 winners
CHANCELLOR = Flaming Page & Mesopotamia
IRRESISTIBLE JEWEL = Flower Bowl & Natalma

Group 3 winners
ANTIOQUIA = Special & Almahmoud
MAGIC MISSION = Natalma & Almahmoud
DEEP SUMMER= Thong & Almahmoud

Anyway, I digress.

By far the most popular RF is crossing Natalma. I need to scrutinise this further, and will do so, but my gut feeling is that the majority of Natalma RF's are the crossing of Northern Dancer and his sisters Raise The Standard and Spring Adieu. Sex-balancing may have some part to play here. Also a quick look at the pedigrees of the two mares and one sees their sires are Buckpasser and Hoist The Flag. Maybe we are seeing an affinity between Northern Dancer and two other top class sires. Or are we seeing Northern Dancer x Northern Dancer again! I do need to have a deeper look but a lot of the Natalma successes will be thus inbred. For instance, Spring Adieu = Razyana = Danehill and there are lots of Danehill x Northern Dancer's stakes winners around.

Now seeing that 60% of the RF's are via just 5 mares I thought I'd have a look at the successful RF's. Of the 3809 RF foals a total of 719 are stakes winners. I would think that any pedigree analyst alive would think 18.9% stakes winners to foals is a win position!

Here's the top 10 in stakes wins order.

Inbreeding to these mares is certainly not a bad thing to do. 

As I have calculated the %SW's to foals I may has well add that two mares did very well. In 2nd place was Lady Angela who was RF in 10 foals. 6 of these, all folaed in Japan, were stakes winners. CRAFT WORK, DREAM COME TRUE, MEINER AMUNDSEN, MOERE TREASURE, NAMURA BIG TIME, ONE MORE CHATTER. The one with the best percentage was Mixed Marriage at 7 from 11! CARRIZO CREEK, CARTOGRAPHY, FATHER THAMES, MR KRISLEY, SUPREME DISCOVERY, T E LAWRENCE and Johar (also Somethingroyal).  The 7 from 11 should possibly be 8 from 11 because we have to count the top hurdler MOVE WEST.

Now for some that did not come out that well

Now a disclaimer. This is only using foals 98, 99, 00 and 01.  Things are not static and maybe using different years would give different results. Also for the worse case the numbers found are quite small so perhaps a pinch of salt is needed.

Grey Flight does not look that great a move though and some people swear by her. The 5 I found for her in the above mentioned timeframe are:
ADJUDI MITSUO
HASNA
WACKY PATTY
I LOVE SILVER
NUCLEAR ASSEMBLY

If I have missed any please let me know. Also looking at these six it is difficult not to notice that top class stallion What A Pleasure features in them. 

Anyway, a lot more investigation still to be done.  The raw numbers does confirm that incorporating inbreeding to superior mares it is a favourable thing to do. However, lots of the successful RF's are often through one and often two top class stallions and it could well be the interplay of these is distorting the results. Either way the one's that work are really high class so the mantra should be to follow whatever breeding scheme suits you but make sure that you inbred to top class breeding stock.

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Since finishing the article I decided to look at those Gr1 winners with RF inbreeding.  Could there be alternative reasons?  I'll link to their pedigrees, give the female inbreeding and suggest another reason other than female inbreeding.  I think there is plenty of evidence here to suggest that if there is power in the female inbreeding it nearly always comes through top class stallions and/or top class brothers and sisters.  

Adrian Parry Copyright 2006