Dr Mark Kennedy
Dooneys Gate and Ornais suffered fatal injuries in a race in which 10 horses either fell or unseated their riders.
Kennedy, senior lecturer in animal welfare at Anglia Ruskin University, which has campuses in Cambridge and Chelmsford, said more should be done to improve horse welfare at Aintree.
"The risk of death in flat racing is approximately one fatality per 1000 horse starts and for steeplechases, such as those at the Aintree meeting, it is around six per 1000 starts," Kennedy said.
"On average then in the larger jump meetings, such as the three-day Grand National, we can expect around three horse fatalities.
"Humans are notoriously bad at understanding risk," he said.
"An analogy that might be easier for us to relate to is to consider an individual driving their car every day of the year.
"According to government statistics from around 10 years ago, the number of human fatalities per 1000 car journeys is 0.00004.
"If the risk to the driver was the same as the Grand National - six deaths in 1000 - then you would be lucky to still be alive after six months," Kennedy said.
"I doubt many of us would accept this and yet we think it is acceptable for horses to be exposed to these risks."
Kennedy, who lectures in the university's Bachelor of Science courses in animal behaviour and Welfare and equine studies, noted that the British Horseracing Authority recorded all racecourse injuries and fatalities, analysed them for contributing factors and then made recommendations.
For the Grand National course, the authority has changed several fences and stipulated the type of ground conditions acceptable for the running of the race, but there is still significant risk, he said.
"What we need is greater debate about what is going on here in the UK.
"On the one hand you have the abolitionists that state that no rate of fatality is acceptable while on the other hand you have people ... who consider it a sport which entertains and which contributes to the culture of this country.
"The only way of reducing risks even further is to discuss the subject more openly.
"My own view, however, is that it cannot be morally acceptable that we can statistically expect the carting away of three dead horses every time we have a major multi-day jump meeting like the Grand National."
The four-mile and four-furlong Grand National race is the centrepiece of the three-day meeting on Merseyside.