They make a major appeal when their bloodlines are analysed to measure staying aptitude.

Philamore from the same ancestry as the wonder performers Phar Lap and Sunline won last weekend’s 2000m Avondale Guineas most impressively from Mount Street. The third Derby hopeful on stamina potential Russian Pearl, fresh from his 1600m Group I Bayer Classic success, remained at home.

There is a medium called dosage, which can provide some guideline to staying potential. Certain key horses in the breed have the flair to transmit certain aptitudes ranging from brilliance through to 1600m, middle distances and endurance potential.

These key performers are known as “chefs-de-race” and have consistently left their impact on the breed for several generations.

If a horse being analysed has multiple speed presences he should come to hand early. On the other hand those with a bias towards stout presences should run on over ground.

The current dosage exponent Dr Steven Roman has devised an index to measure distance aptitudes.

A basic score is 2.40, which is the standard figure for 1600m (one mile). A runner with a smaller or sharper figure (say 3.50) is likely to be speedy in potential while a 1.50 index suggests stamina potential.

With the New Zealand Derby research the big three on stamina potential are Philamor (0.96), Russian Pearl (1.04) and Mount Street (1.30).

It is important to remember that dosage reviews are a guideline. Generally they are quite dependable but they can overlook the human input into a horse’s ability. Top trainers can have the flair to develop milers, for instance, into top performers at the longer classic distances. They are talented conditioners.

Where the 2003 New Zealand Derby is concerned the favourite Waitoki Dream is the nemesis for the dosage observers.

He races like a staying toff but on paper has a 2.75 dosage index, which focusses on 1600m.

His sire Pentire, who won the 2400m Group King Geoge and Queen Elizabeth Stakes in Britain, has only a 1600m bias under the Dr Roman scoring system. However, he mixed his form in some other staying assignments. In the meantime trainer Kevin Cullen will be applying the finishing touches to ensure Waitoki Dream is adequately prepared for 2400m on Boxing Day. He will put the dosage reviews to the test.

Here are thumb nail sketches for the leading 10 Derby contenders, according to the TAB fixed odds review earlier this week.

3g WAITOKI DREAM $4-50
(Pentire Calm Lover, by Spectacular Love)
No 7 All Quiet family, descending from Eleusis. Dam a sister to Calm Harbour. Same family as Game.
2.75 1600m dosage index. Ample speed and class.

3g PHILAMOR $4-50
(Generous--Plaid, by Morcon).
No 2 family descending from Miss Kate. Same branch as Sunline and Phar Lap.
0.96 dosage index. Sound staying type.

3g MOUNT STREET $10.00
(Kilimanjaro-Real Trier (Aus) by Turf Ruler)
No 8 family, descending from 1913 GB mare Joan Alone, who went to Australia. Family of VRC Derby winner Pride Of Egypt.
1.30 middle distance index. Has speed, class and stamina.

3c RUSSIAN PEARL $10,00
(Soviet Star-Velinda, by Veloso)
No 16 family ex French grandam, featuring the illustrious half brothers Dastur and Bahram through Fille de Salut.
1.04 dosage index. Staying aptitude.

2g MAROOFITY $13.00
(Maroof-Howkudai, by Don’t Forget)
No 22 family, Grandam a USA import. Family performers did well in Europe. Maroofity a leading NZ juvenile last term.
1.95 dosage index. Has a middle distance forte.

3c FIREWHEEL $12:00
(Entrepreneur-Imnposera,by Imposing).
No 1 family. Fifth dam Helen Of Troy (GB), descending from the great Chelandry breed, Dam won the Caulfield Cup.
1.45 dosage index with middle distance bias.

3g MR SLEEMAN $16:00
(Danske-Lantello, by Lanfranco).
No 1 family descending from Mr W R Stead’s great mare Granada. Family of Skylit (Telegraph Hp).
1.22 dosage index. Class and stamina.

3g CUT THE CAKE $20:00
(Yamanin Vital-Icing On The Cake, by Straight Strike)
New Zealand colonial family. Related to a noted breed from Foxton allied with Pinnacle Ridge and Bill Wills Cream Puff.
2.15 dosage index. A miler in type with speed and class.