"The European Commission is committed to protecting consumers from intolerable health hazards, which may be associated with residues of veterinary drugs or even of non-licensed or forbidden substances in animal products intended for human consumption. For this purpose legislation on veterinary drug residue control has been established as the indispensable basis of the consumer protection within the EU . . . .
All activities of these laboratories must be in line with the provisions of this comprehensive legal act and therefore comprise not only the development of appropriate state-of-the-art residue control methods, but also a number of other duties of vital importance, such as the establishment of a uniform quality management system and above all a generally harmonised approach to residue control in all Member States." 
OVER THE PAST several years the EU food-animal drug initiative has engaged in a concentrated effort to eliminate any horses who have been administered any prohibited substance bound for slaughter from entering the food chain.
A "passport" system has been established that requires documentation of medication history and express notification by owners that their horses are intended for slaughter (or not). 
Indeed an honorable and disciplined approach to an existent problem associated with the administration of medications to animals for human consumption. But does it recurrently apply to horses here in NA and elsewhere? According to regulations imposed upon North America in July of 2010 apparently so.
An effort spearheaded by Int'l Fund for Horses alerted EU officials of drug violations resulting in the export of adulterated horse meat from North America for human consumption to its countries. Persistent lobbying eventually moved the EU to mandate a six-month quarantine on horses intended for slaughter in Canada and Mexico, who have not been specifically bred for that purpose. 
As of July 31, 2010 an Equine Identification Document (EID) is required for every horse that enters the slaughter pipeline regardless of country of origin and/or slaughter (i.e. United States, Canada and Mexico). This document must reference a visual description of the horse and a list of any medications that have been administered in the six months preceding slaughter.
To date, the success of this initiative in NA is seemingly less than satisfactory; the slaughter of thousands of Thoroughbreds, Standardbreds and Quarter Horses continues all of whom undoubtedly have received phenylbutazone within this time period. After all “bute” is a legal and permissible race day drug in North America, and is not limited to Thoroughbred racing.
More importantly, what this measure fails to consider is the fact that Phenylbutazone is on the forbidden medication list wherein no horse that has ever been administered “bute” is permitted to enter the food chain. 
Given that the majority of horses in North America continue to fall within this category clearly the export of horse meat to EU nations is not compliant. And this is only a single drug among the countless others routinely administered for various reasons.
Since there is "technically" no industry in North America that specifically breeds horses for their meat together with the widespread conventional use of phenylbutazone, one must come to the conclusion that the vast majority of these EIDs must be falsified.
There is nothing to suggest otherwise.
In fact, the European Commission Food and Veterinary Office (FVO) found serious violations during inspections conducted in November and December of 2010 of EU regulated plants in Mexico slaughtering horses for human consumption. Among other violations not surprisingly the matter of prohibited drugs was cited. 
In terms of the presence of inadmissible drugs, the situation in Canada will prove to be no different as the source of the horses is consistent with those that enter the slaughter pipeline to Mexico.
But is it really any different elsewhere in the world?
Some countries do raise horses specifically for slaughter such as in France and other European countries.
"In Austria and northern Italy, the Haflinger, which is an expensive, prized breed of large pony/galloway here in Australia, is bred for the horse meat industry. They are run in the alps in herds just like one would cattle, and are slaughtered when they reach the desired age. They are well cared for, but they don’t have names, they don’t get groomed, stabled or pampered. They are livestock." 
On a global basis this is not the norm since horses are inefficient at converting grass and grain to muscle compared to cattle for example. In contrast, horses are typically raised as pleasure or sport animals — not intended for the food chain — and once their usefulness or monetary value declines they are slaughtered for their meat. Not only is this a convenient solution but it also turns a modest profit to their owner.
In fact, many of the countries in the EU that consume horse meat on a regular basis — Hippophagists, if you will, the act of feeding on horseflesh — import it from the very countries that do not farm horses specifically for their meat (both EU members and non-members). Many of these horses invariably have been administered phenylbutazone at some point in their lives.
Table 1. Selected EU Countries: Horse Meat Imports (2008 FAO Statistics) 
This list is not exhaustive, nor does it take into account non-EU countries that import large quantities of horse meat from sources not expressly farmed for their meat and equally at risk.
For example in the same year non-EU members Russia, Japan and Switzerland imported 20,263 tonnes, 5,255 tonnes and 4,729 tonnes respectively from a variety of the countries of origin in Table 1. It is merely a sampling of the facts and does not include horse meat trade amongst other EU members.
One can rest assured that this horse meat trade between various countries — EU member or not — is in no way intended for pet food.
The argument to consider is that in spite of the stringent policies in place, members of the EU fail to abide by their own rules, whether that be an importer or exporter (e.g. Ireland and the UK ). Moreover these 2008 data do not fully disclose the increase in sport and pleasure horses entering the slaughter pipeline in several countries due to the economic downturn over the past 3 years, notably Ireland and the UK.
If truth be told, the slaughter of sport and pleasure horses for human consumption occurs in an abundance of the 27 member countries of the EU regardless of whether horses are expressly farmed for their meat in any particular country. This means that the figures cited in Table 2 above merely kiss the surface of the problem.
A few examples will serve to paint a clear picture of reality.
"Since Sweden has become very strict with what horses can be slaughtered there, the horses who don't have a 'clean' passport are being subject to a 'black market' and illegally transported to Italy— then their meat still comes back, packaged, for the Swedish grocery stores. . . ."
"Since the borders with the EU has opened, customs (border control) of animals in practice completely ceased. Swedish horses — which by law must have a veterinary certificate to leave the country — can now easily be shipped out, without anyone noticing. Through long and sometimes painful movements, which veterinarians and animal inspectors confirm, the horses finally are submitted to slaughter plants, in France, Belgium and Italy."
"The Swedish black market has ramifications to include Belgium, Eastern and Southern Europe and is a so far unknown part of an otherwise condemned and very large meat processing industry."
"It is difficult to follow each individual horse because the animals can change hands and papers several times on the road to the ultimate destination in Southern Europe", said Johan Beck-Friis of the Swedish Veterinary Association."
"From the harness race tracks disappear without a trace, some 1,000 horses each year. We have good reason to believe that unscrupulous horse dealers are buying up these individuals." 
"Secretary Jenny Lupton told Horsetalk there was a culture of eating horse meat in France, and some horses were raised for that purpose. Others went to slaughter when their owners no longer wanted them . . . . "We have also seen British thoroughbreds in markets over here," Lupton said. "I think it has been going on for years." . . . . She fears it is the tip of the iceberg, with the majority going straight to slaughter." 
New figures released by the government show that last year the total of all horses and ponies slaughtered for meat in England, Scotland and Wales rose to 7,933, representing a 50% increase on the average number slaughtered in previous years.
"A lot of that increase, at least half, will be thoroughbreds," said Dene Stansall, an adviser to Animal Aid, a charity that campaigns against the use of animals in sport." 
"While statistics on the breed of horse slaughtered are not recorded by officials, the majority (60-80pc) are believed to be thoroughbreds.
John Joe Fitzpatrick from Shannonside Foods in Straffan says 80pc of the 2,200 horses slaughtered at his purpose-built plant last year were thoroughbred and 60pc would have raced.
The horses are sent for factory disposal for numerous reasons, including poor track performance, career-ending injuries, temperament issues, stable vices and lameness.” 
"According to several surveys, carried out in Italy, the meat coming from sport horses seems more appreciated by consumers, due to the more intense colour, subtler muscular fibres, lower fat content than the meat from heavy breeds." 
Further, Belgian-owned horse meat companies in South America (e.g. Argentina) where sport horses routinely end up in the slaughter pipeline export this meat to Belgium, Italy and France among other EU countries for human consumption. 
Clearly the regulations are in place, but apart from the horses raised for their meat and some feral horses, overall the remainder, which proves to be a large portion of the whole, does not meet EU criteria in terms of "intended for human consumption."
Despite all of the rules and regulations imposed by the EU coupled with the prohibited substances lists enforced by the global horse racing industry, in particular the Fédération Équestre Internationale (FEI) and International Federation of Horseracing Authorities (IFHA) this anomaly of sorts can be ascribed to a single drug – phenylbutazone aka “bute” – the omnipresent and most widespread drug of choice for the relief of lameness in the horse.