Lasix: What the Rest of the World Does

Yesterday's post addressed some of the scientific findings regarding Lasix use. Gina Rarick, an American who trains in France, where Lasix cannot be used on race day, but is permissible in training, wrote to ask whether the discussion at the NTRA/AAEP/RMTC "Summit" had dealt with the possibility that repeated Lasix use contributes to the leaching of calcium and other minerals from the horse's system and therefore to increasing fragility in a horse's musculo-skeletal system and, ultimately, to a higher rate of fatal breakdowns. Good question. My own, admittedly amateur, review of the available information suggests that it is definitely established that the use of Lasix lowers a horse's levels of calcium in the blood. What's not so clear is whether that short-term calcium loss translates into long-term bone fragility and more frequent breakdowns. Lots of opinions on the subject, but, at least as far as I can determine, not a whole lot of science. I'd love to see a well-designed study on the topic.

Science notwithstanding, it's true that, for whatever reason, the US and Canada stand alone among major racing jurisdictions in permitting race-day use of Lasix. Here's what other major racing countries do, as reported to the "Summit":

Australia: No race-day Lasix permitted, with a suggested withdrawal time of 48 hours (in practice, that means that a prudent trainer won't give a horse Lasix less than 4-5 days before a race). Trainers are permitted to use Lasix for horses in training, and some do before a breeze. Horses are reported as "bleeders" only if they show bilateral epitaxis (bleeding from both nostrils), either after a race or in training. Bleeding that is evident only on scoping, even at the performance-affecting 3/4 levels, doesn't count. If a horse is observed bleeding, then it's taken out of training for at least three months and isn't permitted to race again for at least three months, and then only after a 5/8ths-mile gallop with no bleeding.

France : Similar to Australia -- no race-day Lasix with a 48-hour withdrawal time, but Lasix use permitted in training at the trainer's discretion. No specific rules on barring horses that have been observed to bleed, but tthey do have to pass a vet exam before being allowed to race again.

Germany: Lasix appears to be banned both on race day and in training, and horses are banned for breeding purposes if they've ever raced on drugs, or if they've ever bled.

Hong Kong: The Hong Kong Jockey Club, which runs the tracks, licenses owners, trainers and jockeys, makes and administers the rules, and runs the test lab (a collection of power in a single entity that, I suspect, makes Frank Stronach salivate), does not permit Lasix either on race day or in training. There are two categories of "bleeders." If a horse bleeds from the nostrils, it's categorized as an "official bleeder" and cannot race for at least three months, pending an official vet exam. After a third bleeding episode, the horse is barred from racing for life. The second category is a horse that appears to the stewards to have performed below expectations, in which case the stewards can order a vet exam and, if the horse scores a 3 or 4 rating for blood in the trachea, then they're required to have an official vet exam after a track gallop and can't be entered in a race for at least two weeks. In the past five years, Hong Kong reports that 0.5% of all horses were "official bleeders," and another 0.6% were reported as having "substantial blood in the trachea." Over the same time period, just under 1% of the Hong Kong race horse population was compusorily retired because of bleeding.

Ireland: No Lasix on race day, though it can be used in training. The definition of bleeding is very tight, with only horses that bleed visibly at the nostrils being classified as bleeders and subject to mandatory time off before returning to the races. Under that definition, only some 0.15% of starters are labeled as bleeders.

Japan: Lasix is banned for 10 days prior to race day, though it may be used in training, subject to the 10-day limit. Bleeding is defined as visibly bleeding from the nostrils, with no specific rules about blood that's visible on a scope. Horses that bleed visibly are barred from racing for one month in the first instance, two months in the second, and three months in the third. Visible bleeding was reported in between 0.1% and 0.2% in most recent racing years in Japan.

Singapore: No Lasix permitted on race day, though it can be used in training up to 3 1/2 days prior to a race. Bleeding is defined as in Hong Kong, but is reported to occur in less than 0.5% of starters.

UAE (Dubai): No drugs permitted within 48 hours of post time, with a recommended three-day withdrawal period for Lasix, but Lasix is allowed in training. As in most of the other jurisdictions, bleeding is defined as bleeding visibly at the nostrils, and horses are barered from racing for gradually longer periods after each bleeding episode. The prevalence of bleeders is somewhat higher than in other jurisdictions, perhaps because of the climate, at about 0.4% of all starters.

United Kingdom: No Lasix on race day, though it can be used in training.

To summarize: all the major racing jurisdictions outside North America ban the use of Lasix on race day. Most jurisdictions, Hong Kong and Germany excepted, permit the use of Lasix in training, as long as it's not given within a defined period prior to a race. And most of the jurisdictions report very low rates of "bleeding," by which they almost all mean that a horse bleeds visibly from both nostrils; the rates range from a low of one per 1,000 starters up to a high, in Hong Kong and Singapore, of perhaps five per 1,000 starts.

So how can we reconcile the fact that, according to the South African study that I reported on yesterday, "most horses bleed," with the very low rates of bleeding reported in non-Lasix countries?

A few possible explanations stand out, though there's little science so far to prove or disprove any of them.

First, training practices differ substantially as between North America and most of the rest of the world. Here, most horses train at the race track, are exercised for comparatively short times, and get comparatively more speed work, with racing-speed breezes. Elsewhere, it's more common to train away from the track, in a less pressured atmosphere. It's notable that the relatively higher rates of bleeding in non-Lasix jurisdictions occur in those places -- Hong Kong, Singapore and Dubai -- where horses do train at the race track.

Second, most jurisdictions' definitions of bleeding don't include horses that score a 3 or 4 when scoped, even though those hores are clearly compromised in performance. According to the South African study, nearly 10% of horses have serious tracheal bleeding without Lasix (reduced to essentially zero with Lasix), enough to affect their racing performance.

Third, there's much more dirt racing in the US than elsewhere. It's not clear how that affects the tendency to bleed, and the South African study was conducted with turf racing, not on dirt.

Fourth, there are racing style, distance and pedigree differences. More races in the US are at short distances, with horses running at maximum effort all the way. In many turf-racing jurisdictions, horses tend to gallop along, at less than maximum effort, for a good part of the race

Could US racing survive without race-day Lasix? It would undoubtedly require major changes in training patterns and, ultimately, in breeding patterns as well. Is it possible? That's a question for tomoorow's post.