More than 1,200 farms have gone out of business in the South West during the past four years.
Figures from the The Department for Environment Food and Rural Affairs (Defra) show the decline since the foot and mouth outbreak in 2001.
In Devon the number of farms has decreased from 6,110 in 2000 to 5,240 in 2004 - a drop of 870.
The numbers in Cornwall and the Isles of Scilly have fallen by 346 from 3,903 to 3,557.
The figures were obtained using Defra's annual agricultural census.