The Boylesports Irish Grand National at Fairyhouse on Easter Monday will this season cater for three reserves.
Final declarations for the €275,000 feature must again be made on Friday, but a maximum field of 30 will change if any horse is declared a non-runner up to 10am on Sunday.
Fairyhouse general manager Peter Roe told the Irish Times: "We had a reserve system in place once before, in 2011, but that was when problems with the track meant we were reduced to a maximum of 25 horses.
"The first reserve that year was Beautiful Sound who'd run well at Cheltenham and was the ante-post favourite.
"But he didn't get in, and it was only an hour before the first race that day that he was confirmed a non-runner which made a mockery of ante-post betting.
"Previously the Tote couldn't cope with more than 30 names but that's been ironed out so on Good Friday, 30 horses, plus three reserves, will be declared.
"And should for any reason there be a non-runner over the weekend, reserves can be declared in their place up to 10am on Sunday morning."
