obstacle, the incline on the landing side was levelled out and the drop on was reduced by between 4 and 5 inches (10–13 cm) to slow the runners. Other fences have also been reduced in height over the years, and the entry requirements for the race have been made stricter. Screening at the Canal Turn now prevents horses from being able to see the sharp left turn and encourages jockeys to spread out along the fence, rather than take the tight left-side route. Additionally, work has been carried out to smooth the core post infrastructure of the fences with protective padding to reduce impact upon contact, and the height of the toe-boards on all fences has been increased to . These orange-coloured boards are positioned at the base of each fence and provide a clear ground line to assist horses in determining the base of the fence. 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 each at the 1996 and 1999 Nationals despite smaller fields and the possible ramifications concerning the speed of such races in addition to recent course modifications (part of the "speed kills" argument). Some within the horseracing community, including those with notable achievements in the Grand National such as Ginger McCain and Bob Champion, have argued that the lowering of fences and the narrowing of ditches, primarily designed to increase horse safety, has made matters worse by encouraging the runners to race faster. During the 1970s and 1980s, the Grand National saw a total of 12 horses die (half of which were at Becher's Brook); in the next 20-year period from 1990 to 2010, when modifications to the course were most significant, there were 17 equine fatalities. The 2011 and 2012 races each yielded two deaths, including one each at Becher's Brook. In 2013, when further changes were made to introduce a more flexible