I posted my comments about the Melbourne Cup on a non-horse forum and received the following question:

Hi there,
Don't know if you are still writing for thoroughbred mags but I'm a bit of a bloodline buff and noticed this morning, while looking at Studbook site, that Makybe Diva and Shocking share a few ancestors. The main one that keeps popping up, and not always in relation to Danehill, is the mare Natalma. She appears on sire line for MD as Danzig and Nureyev are full brothers. Also on sire and mare line for Shocking, mated to various stallions over various generations, Hoist the Flag, Buckpasser, Nearctic, Northern Dancer.
Other prominent ancestor sires they share besides Danehill are Riverman and Roberto.
Thought it may make interesting reading as it looks like Shocking is giving the next Melbourne Cup a whirl and as he's only 4 now he could be worth watching!

If you pursue this or something similar on breeding of Cup Winners (and it's published) I'd love to know what it appears in as you write well and it's easy to understand.


My response:

Hi,  Great to hear you're interested in breeding.  Northern Dancer is the most influential sire of modern times.  Even though he only served what are modest books by current standards - 50 was a full book back in his day - he produced 25% stakes winners to foals (the average is only 1.5%).  His sons, like Danzig, Nureyev, Sadlers Wells, Nijinsky dominate the stallion ranks of today via them and their sons, grandsons etc.  The top two stallions in Aus are descended from him:  Redoute's Choice is by Danehill, by Danzig and Encosta de Lago is by Fairy King by Northern Dancer.  Fairy King is a full brother to Sadler's Wells, while Nureyev is a 3/4 brother (having the same sire and their mothers being siblings).  Danzig is from a different female line to these three, but has had a massive influence in the southern hemisphere, particularly through Danehill.  Of the nearly 800 stallions standing in Australia this season over 150 are by Danehill or his sons!!

Shocking on the other hand is by Street Cry (a grandson of the influential Mr Prospector - a rival to Northern Dancer) from a Danehill mare. 

Makybe Diva is by a son of Danehill and also carrys two other lines of Northern Dancer in her pedigree (one extra in her dad, and one in her mum).  This amount of Northern Dancer (3 occurances in 5 generations) is becoming more and more common in the industry.

To further confuse things, the 3rd top stallion in AUs is More than Ready; who is by Southern Halo by Halo.  The Halo line is separate to the Northern Dancer line in terms of sire line, but Halo and Northern Dancer share the same female line.  Northern Dancer's dam is Natalma whose dam is Almahmoud.  Halo is out of Cosmah, another daughter of Almahmoud. 

There is really no escaping Northern Dancer or his family in the current commercial thoroughbred population!  There are some outcross stallions out there that offer hope.  Street Cry, in some ways, is one of them, although his damsire is Halo! 

The seemingly intense inbreeding that this causes isn't much of an issue for the thoroughbred population.  In most cases, the actual inbreeding is further back than 4 generations (and how many people know their family back that far to check their own inbreeding!).  And the other thing is that thoroughbreds will always be judged on one thing - the winning post.  So any faults, even those caused by inbreeding, are bred out of the population.