Veterinary checks on all runners and a study of the going and field sizes have been recommended by a report into horse deaths at the 2006 Cheltenham Festival.
The Horse Racing Regulatory Authority (HRA) held an inquiry after nine horses died at the four-day fixture in March.
The HRA said it was unable to reach a definitive explanation for the high number of fatalities.
Racecourse officials said the number of deaths was "unacceptable" and pledged to act on the recommendations.
The report makes seven key recommendations, including a mandatory pre-race veterinary review of all runners at the Festival.
It suggests a number of areas for the racecourse executive to consider, including the conditions of the National Hunt Chase, safety factors, the siting of certain obstacles, plus maintenance of take-off and landing areas
Three runners died in the four-mile National Hunt Chase, which is for amateur riders and is the Festival's oldest and longest race.
The report says course officials should review the race's distance, maximum field size and entry conditions for horses and riders.
Another six horses died in other races at the meeting, and two more have subsequently been put down as a result of injuries sustained at the fixture.
Racing cannot afford to be complacent
HRA chairman John Bridgeman
The HRA said Cheltenham's long-term Festival fatality rate was twice the national average at other meetings.
The course will be asked to consider whether it should aim for going conditions to be easier than 'good' because fast, dry ground is considered more dangerous.
"Clearly this is not straightforward in the context of March weather and the risk of creating extreme ground, but statistical evidence is clear that the risk of injury increases on quicker going," said the report.
HRA chairman John Bridgeman said: "Whilst we all recognise that horse racing carries an element of risk for its participants, we are determined to minimise those risks through regulation and best practice."
Cheltenham managing director Edward Gillespie said the 14th fence, at the top of the hill on the new course, has been resited.
The Festival stages 24 races over four days
And fences on the new course are being widened to help provide more fresh, unraced ground specifically for the Festival.
He said a feasibility study was being undertaken into adding a third chase and hurdle course at the Gloucestershire track.
Cheltenham's managing director Edward Gillespie said: "In excess of £3m has been spent at Cheltenham in the last six years on projects that are specifically related to horse welfare.
"These include widening the course, improved routes to the start and a veterinary centre.
"We look forward to implementing these recommendations for the 2007 Festival and continuing to work with trainers and welfare organisations."