An MP has challenged critics of a badger cull programme – designed to curb the spread of bovine tuberculosis – to bear witness to the "devastation" wrought on Westcountry farmers.

Dan Rogerson, Liberal Democrat MP for North Cornwall, conceded there are "understandable doubts" over the controlled shooting of infected animals.

But Mr Rogerson, a member of the cross-party Environment Select Committee, examined evidence in the last Parliament supporting a targeted cull.

Last week, Environment Secretary Caroline Spelman announced plans that could lead to the creation of 40 badger culling zones, with most of them likely to be sited in the South West, from next year. Two "pilots", to be carried out by trained marksmen, will take place first.

In a Commons debate, Mr Rogerson said: "Some members of that committee went into the inquiry opposed to a cull, but came round to that view (that a cull is beneficial) having seen the evidence."

He asked whether Mrs Spelman agreed that it "would be great if those who have understandable doubts about a cull could come to rural areas, such as Cornwall, and see the devastation on the ground so that they could understand that we need to do something about this issue?"

The vast majority of 25,000 infected cattle slaughtered last year were in the South West.

Mrs Spelman replied: "Nothing compares with visiting a farm in one of the worst affected areas and learning at first hand about the devastation and heartache that repeatedly having to send cattle to slaughter brings."

The controversial decision has been criticised by animal welfare groups, the Labour Party and a smattering of Lib Dem MPs, including Andrew George (St Ives) and Adrian Sanders (Torbay).

A 2007 report on the ten-year Independent Scientific Group (ISG) trial concluded a cull would not "meaningfully" control the disease. The Labour government used the report to justify its decision to refuse a cull.

But the coalition Government contend a more recent peer-reviewed analysis of the same trial shows that the rate of cattle infections continued to drop years later. Problems with displaced badgers spreading the disease also disappeared.

In a Commons debate on the day of the announcement, Mrs Spelman also raised questions over the potential for an injectable badger vaccination, which has been hailed as a more humane alternative to culling. A vaccine can only inoculate healthy badgers against the disease.

She told MPs that trials in Gloucestershire to test the methods – essentially trapping and vaccinating – concluded that it is "possible but impractical and certainly difficult to make affordable".

Ministers have raised the prospect of an oral vaccine for cattle and badgers – seen as a magic bullet – never coming to fruition, although £20 million of state cash has been committed to its development.

Labour MP Kerry McCarthy (Bristol East) told the Government to "stand up to the farming lobby and tackle the impact of cattle movements and farmers allowing cattle that they know to be infected to go to market".

But Mrs Spelman said that among a series of measures announced last week, tighter restrictions on cattle movement was "at its foundation".