AEI/CI Explained

AEI (Average Earnings Index)was developed by the late Joe Estes former editor of The Blood Horse. He wanted to develop a statistical method of appraising the performance at stud of both sires and mares based on the earnings of their progeny annually. Utilizing a numerical index where 1.00 represents the average for the breed, AEI reveals the earnings for any horse relative to his or her peers during the same year. For example, if the average earnings for a 3 year old horse during a specific season was $10,000, and your 3 year old had earned $15,000 during the same season, its AEI would be 1.50.

The CI (Comparative Index) tries to give us an idea of the quality of foals out of the same mares, but sired by different stallions. The aim is to determine whether or not a stallion is improving on his opportunities ( "upgrading his mares") or downgrading mares bred to him. The CI is derived by taking the average AEI of a mares foals sired by different sires. For example, in a hypothetical scenario where a sire was bred to just one mare, and the AEI's for her previous foals were 2.00, 1.50, and 1.00, the sire's CI would be 1.50, the average for the mare's other foals

The majority of sires at stud fail to upgrade their mares during their stud career. In modern times the most successful sire in Australasia has been Danehill whose lifetime AEI / CI figures reveal that he was able to upgrade mares mares bred to him by 51%. It comes as somewhat as a surprise to discover that many stallions considered to be successful in fact downgrade their mares. Many sires are reliant upon the quality of mare bred to them to maintain their lofty reputations.

Below is a list of stallions who have stood in the Northern Hemisphere that are represented in Australasia. AEI / CI figures are freely available for their Northern Hemisphere progeny which allows local breeders an opportunity to assess their performance in those regions. These figures have proven to be a reasonably accurate predictor of the subsequent performance of these sires at stud in Australasia. AEI / CI figures are available for GONE FOR REAL and have been included in the table in an effort to underline the potential which he offers to New Zealand breeders.

Northern Hemisphere Sires AEI / CI

Sire AEI CI Up/Dwn %
Danehill 3.09 2.04 51%
Gone For Real 1.39 0.96 45%
Dehere 1.90 1.60 19%
More Than Ready 2.16 1.95 11%
Helmsman 1.17 1.11 5%
Cape Cross 1.64 1.69 -3%
Van Nistelrooy 1.48 1.52 -3%
Stravinsky 1.74 1.84 -5%
Royal Academy 1.65 1.75 -6%
Tale of The Cat 1.71 1.92 -11%
Elusive Quality 2.04 2.43 -16%
Red Ransom 1.75 2.16 -19%
Anabaa 1.75 2.32 -24%
Storm Creek 1.03 1.56 -34%
Fusaichi Pegasus 1.75 2.70 -35%

Gone West the source of superb turf sprinter milers

It may come as a surprise that Gone For Real is the biggest upgrader of all sons of Gone West at stud in the USA as measured by AEI / CI lifetime figures. Breeders who understand the value of this valuable tool for measuring the performance and potential of a stallion with progeny on the racetrack would be foolish not to capitalize on the opportunity which Gone For Real represents.

Gone West and his sire sons have been responsible for some of the most spectacular sprinter milers on turf in recent years and have commanded extraordinary service fees to match as a result. Gone West has bred world record holders Da Hoss (twice winner of the Breeders Cup Mile on turf, he ran the six furlongs in 1:07 1/5, which is believed to be a world record for a two-year-old ) and Elusive Quality. When winning the GR 3 PokerHandicap by six lenghths Elusive Quality set a new world record for a mile on turf. In Europe his son Zafonic captured the Dewhurst Stakes at two years and the 2000 Guineas at three and was acclaimed European Horse of the Year. Zafonic in an abbreviated stud career produced the brilliant Xaar who like his sire turned into a procession the Dewhurst Stakes by seven lengths. Xaar was crowned European Champion two-year old and 3 year-old. Zamindar the full brother of Zafonic has kept the family tradition going of producing fantastic sprinter milers through with his four Group One winning daughters, Zenda, Darjina, Zarkava, and Coquerelle. His daughters Zenda , Darjina and Zarkava have all won the GR1 French 1000 Guineas ! Mr Greeley the USA based son of Gone West has bred four Group One winners outside the USA, of whom three ( Saoirse Abu, Reel buddy and Finsceal Beo) have done so in Europe and the other Miss Kournikova won in Australia which further underlines the affinity which the Gone West stock have for turf conditions. In 2007 Finsceal Beo won both the English 1000 Guineas and the Irish 1000 Guineas. Attempting to add the French 1000 Guineas to her stellar record Finsceal Beo was thwarted by Darjina whose sire is Zamindar. The result of the 2007 French 1000 Guineas again demonstrates the amazing ability of Gone West and his sons to produce exceptional sprinter milers on turf. The amazing Australian sprinter miler Apache Cat who has captured the hearts of racing fans with five consecutive Group One races is by the relatively unknown Lion Cavern. Lion Cavern just so happens to be an own brother to none other than Gone West.

It is worth noting that Elusive Quality, Zamindar, and Mr Greeley weren't successful at Group One or Group Two level, like Gone For Real they were successful up to Group Three.