More than 1,000 farms in Devon and Cornwall have had TB in cattle in the first six months of the year, according to new statistics.
About 3,500 cattle have been slaughtered in Devon and Cornwall
The figures published by Defra show more outbreaks in the region than anywhere in England, Scotland or Wales.
This is the first time Defra has published county-by-county figures for bovine tuberculosis.
Devon had 673 farms under restrictions after cattle reacted to the TB test. In Cornwall, the figure was 474.
As a result more than 2,000 cattle from Devon were slaughtered and nearly 1,500 from Cornwall.
The South West National Farmers' Union says the new figures suggest it could be worse than last year.
Regional Director, Anthony Gibson, said: "So far in the first six months of this year there have been 189 confirmed new cases of TB.
"There were 286 confirmed cases last year, so if the trend continues, we could be in line for over 300 cases."
Mr Gibson says the number of cattle being slaughter per new outbreak has risen from six to 12.
Defra is stressing their figures are provisional, and it is difficult to identify trends from them.