After the eradication sweeps of the 50s and 60s, as herds were cleared of reactors and more importantly, remained clear, testing was relaxed to reflect risk. And from annual tests, parishes entered a bureaucratic disease lottery of testing sequence. Depending on the prevalence of cattle reactors, parish and herd testing ranged from every 60 days to once in four years.
Over the last ten years, after badger control in response to outbreaks ceased, the number of reactors has rocketed, meaning the number of parishes hoovered up into annual testing (and thus preMT) has increased dramatically. But test interpretation has not altered - until now. Wales are reducing the number of tests an animal giving an 'inconclusive' result can have. Farmers Guardian has the story.
This is falling into line with European advice. And the previous three 'inconclusive' strikes, having been reduced in England to two, becomes just a single re-test in the Principality who are undertaking an annual sweep of all herd tests.
A comment on the posting below, firmly opining that 'of course cattle give TB to badgers and other mammals', has gained credence with the chatterati (as our partner labels such empty vessels with less than a single collective brain cell between them.) Thus we remind readers of previous expensive and ineffective cattle carnage under Liam Downie in Ireland and William Tait in West Cornwall. And reiterate the minister's reply to PQs about the total success of the Thornbury badger clearance:
"No confirmed cases of tuberculosis in cattle in the area were disclosed by the tuberculin test the the ten year period following the cessation of gassing" Why would that be, we asked? Anything else done? Biosecurity? Extra cattle measures? Pre movement testing? Nope. The answer:
" The fundamental difference between the Thornbury area and other areas  where bovine tuberculosis was a problem, was the systematic removal of badgers from the Thornbury area. No other species was similarly removed. No other contemporaneous change was identified that could have accounted for the reduction in TB incidence within the area" 
Tightening up cattle controls will only work if wildlife reservoirs are addressed simultaneously, and arguably current cattle controls are more than adequate (annual testing and double fenced boundaries), provided the maintenance hosts of tuberculosis are removed.
And if they are not, then no amount of cattle testing or culling will work.
Defra have posted at new figures to August, reinforcing our point.