2013 Grand National to modifications made for the previous year's race, Aintree announced that a number of further changes had been made for the 2013 National. Twelve of the 16 fences on the course were rebuilt with the timber frames within them replaced by a softer material known as "plastic birch". The fences are still covered with at least 14 inches of spruce and will remain the same height. The starting line was also moved 90 yards closer to the first fence, further away from the spectators' stands and thereby reducing slightly the overall distance. Aintree and the Professional Jockeys' Association jointly issued
Grand National Parts of the course were widened in 2009 to allow runners to bypass fences if required. This was utilised for the first time during the 2011 race as casualties at fences 4 and 6 (Becher's Brook) resulted in marshals diverting the remaining contenders around those fences on the final lap. Welfare groups have suggested a reduction in the size of the field (currently limited to a maximum of 40 horses) should be implemented. Opponents point to previous unhappy experience with smaller fields such as only 29 runners at the 1954 Grand National, only 31 runners in 1975, and a fatality