A horse and its rider jump over a hurdle in the Tattersalls International Horse trials in Ratoath, Ireland. Irish racehorse trainers and breeders fear a Brexit that impedes the free movement of animals could threaten its success on the track and position as Europe's largest producer of thoroughbreds. REUTERS/Clodagh Kilcoyne

Group CEO of Goffs auction house, Henry Beeby (C), and director of sales Nick Nugent (R), conduct a bloodstock auction after the racing at Punchestown Racecourse in Naas, Ireland. Ireland is widely considered the European Union member most at risk from next door Britain's exit from the bloc, potentially cutting its land route to mainland Europe for exports and hindering trade with its key UK market. REUTERS/Clodagh Kilcoyne

Racehorse 'Sizing John' who won the Cheltenham Gold Cup is seen at racehorse trainer Jessica Harrington's yard in Moone, Ireland. Few sectors are as integrated as the two islands' racing and breeding industries that, according to Horse Racing Ireland, the national authority for thoroughbred racing, contribute over 1 billion euros a year to Ireland's 189-billion-euro economy. REUTERS/Clodagh Kilcoyne

Punters watch a race at Down Royal Racecourse, in Lisburn, Northern Ireland. About 10,000 racehorses travel between Britain and Ireland each year. The proximity and ease of access to the home of so many of the industry's major events plays a central role in Ireland's successful track record, Horse Racing Ireland say.

Of the 28 winners at March's showpiece Cheltenham festival, a record 19 were Irish-trained, including Gold Cup victor Sizing John. REUTERS/Clodagh Kilcoyne

A horse is sprayed with water to cool down after racing at Down Royal Racecourse, in Lisburn, Northern Ireland. Ireland, France and Britain - three of Europe's top horse racing locations - currently have an agreement that predates EU law allowing a horse registered in one country to move freely in all without the need for veterinary examination or inspection. That includes the border between the Irish Republic, an EU member, and Northern Ireland, a British province, where nine out of 10 horses that compete are trained in the republic. REUTERS/Clodagh Kilcoyne

Racehorse trainer Jessica Harrington (L), stands with her daughter, jockey Kate Harrington, during training at her stables in Moone, Ireland. REUTERS/Clodagh Kilcoyne

Punters enjoy the horse racing at Fairyhouse Racecourse in Ratoath, Ireland. REUTERS/Clodagh Kilcoyne

Jockey Oisin Orr looks on after a racing at the Killarney Racecourse in County Kerry in Killarney, Ireland. REUTERS/Clodagh Kilcoyne

Sweat in the shape of a saddle is seen on a racehorse after a race at Killarney Racecourse in County Kerry in Killarney, Ireland. REUTERS/Clodagh Kilcoyne

A groom brings a racehorse into the parade ring before competing at the Killarney Racecourse in County Kerry in Killarney, Ireland. REUTERS/Clodagh Kilcoyne

A punter checks his racecard before a race at the Killarney Racecourse in County Kerry in Killarney, Ireland. REUTERS/Clodagh Kilcoyne

Riders compete in a race at the Killarney Racecourse in County Kerry in Killarney, Ireland. REUTERS/Clodagh Kilcoyne

A bookmaker takes bets from punters at Fairyhouse Racecourse in Ratoath, Ireland. REUTERS/Clodagh Kilcoyne

A bookmaker is pictured at the Punchestown Racecourse in Naas, Ireland. REUTERS/Clodagh Kilcoyne

A bookmaker handles sterling and euro currency at the Punchestown Racecourse in Naas, Ireland. REUTERS/Clodagh Kilcoyne

A punter watches the racing at the Punchestown Racecourse in Naas, Ireland. REUTERS/Clodagh Kilcoyne

A woman looks at her phone after the Irish Grand National at Fairyhouse Racecourse in Ratoath, Ireland. REUTERS/Clodagh Kilcoyne

Punters watch a race at the Punchestown Racecourse in Naas, Ireland. REUTERS/Clodagh Kilcoyne

Punters watch the races at Killarney Racecourse in County Kerry in Killarney, Ireland. REUTERS/Clodagh Kilcoyne

Racegoers attend the Punchestown Racecourse in Naas, Ireland. REUTERS/Clodagh Kilcoyne

The hunt master and dogs walk the track before racing begins at Punchestown Racecourse in Naas, Ireland. REUTERS/Clodagh Kilcoyne

Racehorse 'Vision Des Flos' is led away after being sold to Tom Malone for 270,000 euro (314,000 USD) at a Goffs bloodstock auction at Punchestown Racecourse in Naas, Ireland . REUTERS/Clodagh Kilcoyne