Zenyatta’s official rating of 128 should increase 131 because the general fillies’ allowance of three pounds has been stripped out. Similarly, Rachel Alexandra’s official rating of 127 should rise to 130 to reflect normal race conditions.

This would mean that European 3-year-old colt Sea The Stars would remain the top-rated in the world on 136, but French filly Goldikova would jump to 133 (from 130), followed by Zenyatta and Rachel Alexandra.

Two Irish 3-year-old colts, Rip Van Winkle (129) and Fame And Glory (128), would then drop back to fifth and sixth, respectively.

Gerry O’Gorman, co-chairman of the World Rankings Supervisory Committee and senior flat handicapper for the Irish Turf Club, explained: “I was a bit dismayed last year that Zarkava was not seen as the best horse in the world in 2008.

“We put Curlin and New Approach on 130 with Zarkava on 128. I felt it was very important that with the fillies’ allowance boosting her rating to 131, which she would receive in any of her races, that she should be seen as the best of 2008. The coverage did not reflect that.

“In real terms, we should be adding on the fillies’ allowance to the ratings of fillies, which would put Zenyatta on 131 and Rachel Alexandra on 130.”

He then turned to explain when Zenyatta was rated ahead of Rachel Alexandra.

“Zenyatta’s performance in winning the Breeders’ Cup Classic was rated higher than the best that Rachel Alexandra could achieve. When Rachel won by vast margins—the Kentucky Oaks and Mother Goose—the performances were very hard to quantify, but in terms of running against the colts her performance in the Haskell was her best.

“We were confident that we could rate her on 127 there and it would have been churlish not to call it the same in the Kentucky Oaks which she won 20 lengths in a canter and the Mother Goose in which she very easily beat two opponents.”

There were 14 official handicappers plus various observers from countries all around the world at the WTR conference in Hong Kong last month when the final ratings of the top horses to race in 2009 were decided.

Two North Americans were fully involved—Tom Robbins, who is chairman of the North American Ratings Committee and vice president of racing of Del Mar Thoroughbred Club, and Steve Lym, the racing secretary and director of racing at Woodbine.

“Tom Robbins and Steve Lym were present at our meetings and they both agreed that Zenyatta should be rated higher than Rachel Alexandra, and they both indicated that they will be voting for Zenyatta as Horse of the Year,” O’Gorman said. “They were happy with the ratings of both fillies in relation to other horses.”

The WTR has this year issued some guidance on the handicapping ethos behind the ratings and advice that some of the very high ratings in the past might have been excessive. The decision to do this comes after many racegoers and pundits thought Sea The Stars was the best horse they had ever seen. His rating of 136 is the best since Peintre Celebre on 137 in 1997, with Dancing Brave returning the highest rating of 141 from the International Classifications (the predecessor of the WTR) which were founded in 1977.

O’Gorman commented: “There is no doubt now, viewed in hindsight and in this evolving context, that the level of ratings that operated in the first 15 years of the International Classifications is not consistent with the level of ratings that has operated since the early 1990s to the present time and this occurred for a number of reasons.

“In the context of the current discussion comparing racehorses from different eras, this point needs to be emphasized and borne in mind."

This disparity in level of ratings was particularly pronounced in the first decade of ratings after 1977, so under the circumstances, one would have to seriously question whether the likes of Dancing Brave (141 in 1986), Alleged (140 in 1978), Shergar (140 in 1981), and El Gran Senor (138 in 1984) would have achieved that level of rating were they racing today.

“There is a type of racehorse, which has been especially prevalent of late, who may not be fortunate enough to be part of a vintage crop of horses or who, because of their minimalist nature, will not win in extravagant fashion as Shergar did but rather will do no more than necessary to win the horserace they are involved in,” O’Gorman said.

“We are especially lucky to have seen and marveled at a number of exceptional horses recently who fall within this category. The French filly Zarkava , the Irish colt Sea the Stars, and the American mare Zenyatta were all unbeaten in their main racing seasons, winning their races in the same trademark fashion regardless of the class of opposition and in the process clearly demonstrating their superiority in each race they ran in but equally never appearing to be ‘all out’ in victory with their true extent of their superiority not reflected in the winning margin but rather remaining a matter of speculation.

“Handicappers can quantify the ability of an extravagant winner who ‘shows his hand’ and equally a horse who is ‘all out’ in victory but the winner who keeps something in reserve is far more problematic.

“Handicappers are understandably intent, within reason, on rating a champion racehorse on what he has actually achieved not on what he could, should or would have done if the opposition had been better, if he had chosen to extend himself and show his full ability etc, etc.”

O’Gorman argued that it would have been illuminating if Sea The Stars had stayed in training for the Breeders’ Cup and taken on Zenyatta in the Classic.

“We have had some exceptional horses in 2009 and 2008 and if they had taken each other on then they could have pushed themselves to new heights. The ratings are what these horses achieved, they are not a reflection of their inherent ability. There is no real way of knowing how Zenyatta would done against Sea The Stars.

“We cannot even accurately compare horses in the current generation like Zenyatta and Sea The Stars; they have never met. If they had met, we might know more. Now we will never know.”

Phil Smith, the head of handicapping for the British Horseracing Authority, was also at the press conference. He made the point that ratings depend on “who turns up on the day; Rachel did not go. They decided for reasons they were happy with that they did not want to take the risk, you could say, of getting beat because the surface (at the Breeders’ Cup) was possibly not to Rachel’s liking.”

Zenyatta was raised to 128 after winning the Breeders’ Cup Classic, with Rachel Alexandra then on 125.

O’Gorman explained: “Rachel was then raised two pounds in Hong Kong where we had the WTR meeting, but there was general unanimity between the handicappers that Zenyatta should be ahead of Rachel.

“We are now publishing our ratings six to seven times a year in the immediate aftermath of big races. We do that quickly. At the end of a year, you can look back on the races. We had felt during the year that the American three-year-old colts on dirt were not that great but in Hong Kong we had a fresh appraisal of them. They were not as bad as we had initially thought they were.

“As well as putting up Rachel Alexandra to 127, we also raised Summer Bird to 123.”

Mine That Bird was rated 122 for his Kentucky Derby (gr. I) victory and second in the Preakness Stakes (gr. I).

O’Gorman claimed that Zenyatta before the Breeders’ Cup was “seriously disrespected.”

“One interesting thing about Zenyatta and her perception in North America before the Breeders’ Cup was in the Daily Racing Form on the day of the Breeders’ Cup Classic there were 29 tipsters listed and only six chose Zenyatta, which is astonishing. The Beyer speed figures are not very relevant to synthetic racing and she was seriously disrespected in North America.

“We, as handicappers, were all hoping she would take on the colts so we could see how good she is. Her profile was similar to that of Zarkava in 2008; imperious against the fillies and mares but can she do it against the colts?

“Zenyatta won the Classic in the same way she beat the fillies and mares. Zarkava did the same in the Arc in 2008. I think Zenyatta shocked a lot of locals and I was told in the immediate aftermath of the Breeders’ Cup if the vote for Horse of the Year had been held then she would have won. But I am told there has been a movement back towards Rachel and she is expected to sneak it.”

There have never been three fillies as highly rated in a year as Goldikova, Zenyatta, and Rachel Alexandra.

O’Gorman concluded: “It is a vintage period for fillies.”

Matthew Tester, the main 2-year-old handicapper with the British Horseracing Authority, rated Vale Of York 118 for the Godolphin colt’s victory in the Breeders’ Cup Juvenile, which was the best performance of his age group in North America last year.

The American-trained 2-year-old Jealous Again, who won the Queen Mary Stakes at Royal Ascot in England, achieved an official rating of 115 as against the top juvenile in Europe, with St Nicholas Abbey gaining 124.