Three of the Aintree Grand National fences, including the famous Becher's Brook, are to be made safer.
The changes are among interim measures arising from a review group set up after this year's race when two horses died.
The fatalities followed four at the three-day meeting in 2010 and five the year before.
Since 2000, 33 horses have died at the spring festival, bringing regular protests from animal welfare groups.
The drop on the landing side at Becher's will be reduced by about 12cm, though the height remains the same at 1.47 metres.
Levelling work will be carried out on the landing side to reduce the drop at the first fence which horses often approach too quickly after the start.
The results of a full review will be published in October but it is known that among items being considered is a new post-race wash-down and cooling area for all horses.
Ballabriggs, this year's winner on a warm day, was too exhausted to be ridden into the winner's enclosure and had to be continuously hosed down before recovering fully.