The Grand National field of runners will shortly be finalised - as will the list of Grand National reserve horses.
There are 40 horses in each Grand National, finalised from a longer list of potential entries at 10am on the Thursday before the race.
Reserve horses are horses that could be called upon to to run in the race, who did not make the initial selection.
There are four Grand National reserve horses on the list.
They will replace any horses who drop out, up to 1pm on the Friday before the race. After that, any horses who drop out will not be replaced.
While the reserve horses will be numbered R1, R2, R3 and R4, should they join the main field they will take the number of the horse they are replacing.
The reserve system was brought in for the 2000 Grand National.
