Every month the excellent Australian magazine “Bluebloods” publishes five-generation pedigrees of Group 1 winners from around the planet. (It’s always encouraging when our trans-Tasman cousins get something right; perhaps this comment is not unrelated to the topic of genetics which has been the focus of most of my recent articles).
Anyway, better not be too rude about the green and golds – there’s no credit in demolishing a soft target. Back to the pedigrees. This month’s edition of “Bluebloods” features 24 Group 1 winning pedigrees; I’ve just finished analysing them and they’ve thrown up some fascinating data.
No less than 23 of the 24 pedigrees feature inbreeding in the first five generations; 8 instances involve just one stallion, the other 15 contain duplications of either 2 (7 cases), 3 (6 cases) or 4 (2 cases) stallions and/or mares.
Of these 23 inbred pedigrees, no less than 20 include duplications of Northern Dancer in these first five generations. Other stallions who appear are Mr Prospector (7 times), Hail to Reason (2), Danzig (2), Nijinsky (2) and Blushing Groom (2). Buckpasser, Mill Reef, Never Bend, Sir Ivor, Sadler’s Wells, Storm Cat, Raise a Native, Native Dancer, Konigsstuhl, Tamerlane and Nearctic all appear once. On the distaff side, Special turns up twice; Natalma and Where You Lead make a single appearance.
When we try to interpret any data we’ve got to be careful. The most important question of all is – to what extent do these patterns of inbreeding occur in the racehorse population at large? In other words, if 20 out of every 24 racehorses have Northern Dancer duplications in the first five generations of their pedigrees, then we have proved nothing at all. Moreover, we need to remember that 17 of the 24 Group 1 contests referred to took place in the Northern Hemisphere, that part of the planet where Northern Dancer reigned supreme. And there’s also the question of whether or not our 24 races are a representative sample of all Group 1 events.
So what can we conclude? Well, our analysis may suggest that Northern Dancer is a more significant influence for racing quality than many of us had previously imagined. (You’ll have noticed that Danzig, Nijinsky, Sadler’s Wells and Storm Cat are all Northern Dancer descendants as well). It is generally accepted that inbreeding to this phenomenal animal helps to provide athletic ability, soundness and equable temperament in our mares’ offspring; it’s the dominance of these figures which may be surprising. Secondly, one out cross Group 1 winner out of 24 does not exactly strengthen the position of those of us who support out crossing as a method of improving the breed. Finally, it’s at least interesting that 15 of the 24 pedigrees we’ve looked at contained more than one incidence of inbreeding.
When the Southern Hemisphere Summer rolls around, I’ll repeat this exercise and report back.
