A suspension had been imposed on Guerdat after two of his horses produced positive drug tests in May at the Nations Cup show held in La Baule, France, while the same event also saw one Bichsel’s rides also gave a sample containing banned substances.

The pair's suspensions were backdated to July 20, the date they were notified of the positive tests, while preliminary investigations were carried out by the FEI.

It had been claimed the cases could due to of poppy seeds contaminating the horses feed, which would rid the riders of blame, set to be explored.

Hearings for Guerdat and Bichsel were held via teleconference last Thursday and Friday (July 23 and 24) respectively, with both riders seeking to see their suspensions and those of their horses lifted.

Following the hearings and - based on scientific evidence presented by the athletes - the FEI Tribunal viewed that the likely cause of the positive tests was food contamination and lifted the pair’s suspensions yesterday. 

The investigation is still ongoing, though, with a full decision based upon their cases due at a later date.

Requests by Guerdat and Bichsel to have the suspension lifted on the three horses was denied by the Tribunal, as irrespective of the source of the prohibited substances they had been found in the horses systems and the FEI’s policy is to impose a two month suspension period.

Both of Guerdat’s horses tested positive in May at the Nations Cup show held in La Baule, France, with Nino de Buissonets, the horse which Guerdat rode the Olympic title, providing samples which contained banned substances codeine and oripavine, as well as controlled medication substance morphine.

The samples of his other ride, Nasa, contained prohibited painkillers codeine and morphine, as well as traces of oripavine.

Bichsel’s horse, Charivari KG, meanwhile, returned positives for the banned substances Codeine and Oripavine, in addition to the controlled medication substance morphine, downgraded from banned substance in 2013 in light of the increased number of contamination cases involving poppy seeds.

Three similar cases took place last year with Vitess SC, ridden by Greece’s Monika Martini, Chenna van de Spek of the Netherlands’ Kinka’s Boy and Heartbeat ridden by France’s Julien Anquetin all tested positive for similar substances.

In each of the cases the provisional bans were lifted by the Tribunal in December, although the cases remain ongoing.

Related stories
July 2015: Olympic showjumping champion provisionally banned after two horses return failed doping tests
May 2015: French eventer handed six-month ban by International Equestrian Federation
April 2015: France stripped of Olympic eventing qualification place after positive test at World Equestrian Games
September 2014: France face disqualification from Rio 2016 eventing after horse fails test