The International Equestrian Federation announced the decisions against Khaled Abdulaziz al-Eid and Abdullah Waleed Sharbatly, whose horses tested positive for anti-inflammatories at separate events in the Middle East.
Al Eid, the 2000 Sydney Olympics bronze medallist, and Sharbatly, who won silver at the 2010 World Equestrian Games, had their cases heard in April.
Saudi Arabia’s Equestrian Federation said in a statement that it was “deeply disappointed” with the findings that led to the ban for the two riders. It said it will appeal in the Court of Arbitration of Sport.
The FEI suspended both riders to October, backdating the suspensions to when they voluntarily suspended themselves in February, on news of the positive tests for controlled medications, which are prohibited in competition but allowed outside events.
The FEI said al-Eid failed to prove his horse Vanhoeve was exposed to phenylbutazone in an allegedly contaminated stable during a Riyadh event.
The governing body said it was the same situation for Sharbatly, whose horse Lobster 43 was found to contain oxyphenbutazone, a metabolite of phenylbutazone, during a meet in the United Arab Emirates.