The incidence of tuberculosis among cattle has soared by 28%, according to the latest DEFRA statistics.
Provisional statistics show a 24% increase in the number of new TB incidents in the first nine months of 2008 compared to the same period in 2007.
Combined with a decrease in the number of herds tested over the same period, this equates to a provisional overall increase in the TB incidence rate of 28%.
Monthly bovine TB figures were released by DEFRA on Wednesday (19 November).
They suggest some 47,564 tests will be carried out on herds during 2008, resulting in 3379 new herd incidents.
The statistics prompted the Liberal Democrats to call on the government rethink its policy on bovine TB and badger culling.
Lib Dem shadow DEFRA secretary Roger Williams said: “These figures will be of major concern to livestock farmers.
“Not only has there been an increase in the incidences of bovine TB but the number of tests has decreased, which could be masking an even bigger problem.”
A government-backed vaccine to combat bovine TB in cattle is unlikely to be available until 2015.
Mr Williams said: “By the time the vaccine is available for widespread use it may be too late for many livestock farmers.
“I urge the government to rethink its policy.”