More Evidence the UK's Badger Cull Isn't the Best Way to Prevent TB in Cattle

Badgers, with their furry humbug-like faces, look pretty benign. But over the past few years, they've been blamed with the spread of bovine tuberculosis (TB), and the UK government has been on a controversial mission to cull the crap out of them ever since.

TB in cows can cause significant harm to the agricultural industry, with 9 million cattle testing positive for the disease in 2014. The UK trialled badger culling in 2013, and again in 2014. The culls are not currently UK-wide at the moment, but were rolled out in Dorset, Gloucestershire, and Somerset earlier this year. Since the start, opposition towards culling has been fierce, with many asserting that this strategy to prevent bovine TB doesn't work.

A new study published in the journal of Stochastic Environmental Research and Risk Assessment uses statistical modelling to support the claim that culling badgers might not be the best strategy against bovine TB. Instead, it corroborates research that suggests that more focus must be placed on controlling the spread of disease among the cattle themselves.

Alistair MacMillan, a veterinary advisor to the Humane Society International, a nonprofit animal conservation organization, told me over the phone that while the UK's Department of Environment, Food and Rural Affairs (DEFRA) had invested in a lot of bovine TB prevention strategies, their efforts thus far hadn't been so effective.

"In this new paper, the science is supporting what we [experts in veterinary disease control] already knew, but just doing that in a more sophisticated way," MacMillan, who wasn't involved in the new study, told me. MacMillan, who had experience dealing with bovine TB during his former years at DEFRA, added that it was important to move the focus from culling badgers to finding and controlling the spread of disease within the cattle themselves.

"It's important to test the cattle frequently," he said. "In summary, they've shown that testing the cattle more frequently is a more powerful intervention than culling badgers," said MacMillan.

In the study, the researchers describe using publicly available data from DEFRA to work out how effective current bovine TB management strategies are at a regional level—in Wales, Scotland, and the rest of the UK.

"We performed time-series analyses (using a model to predict future outcomes from pre-existing data) on tuberculosis prevalence in cattle in different regions in Great Britain, and we tried to link that with the control strategies employed," Aristides Moustakas, co-author of the study at Queen Mary's University, told me over the phone.

The researchers discovered that while parts of the UK were using badger culls, Scotland employed incidence-based testing, and Wales frequently tested cattle—once every year or more. They found that compared to other areas, Scotland had low incidents of the disease, and Wales had the most rapid decline of TB in cattle.

"Scotland and Wales both have a declining number of new herd incidents [outbreaks of TB] as well as herds not TB free and thus the current programme applied, all else being equal, appears to be leading to eradication or control of the disease," write the researchers.

"So the most rapid decline was in Wales after 2010 when they decided to implement more frequent cattle testing, while in English regions TB is actually increasing," said Moustakas. "With DEFRA's own data, we found that more frequent TB testing led to better control."

This doesn't necessarily mean culling is ineffective; the researchers weren't able to specifically test the efficacy of culling as, according to Moustakas, this data is not publically available. He added, however, that it was "interesting to note that there's no culling scheme in Wales, where the researchers found the most rapid decline of TB."

Moustakas suggested that a more frequent testing policy be adopted throughout the UK. This view is also supported by Macmillan, who in a press statement said, "Frequent cattle testing is particularly important as the sensitivity of currently available diagnostic tests is not very high, meaning that cattle incubating TB are not detected and are allowed to remain in the herd to infect others over the following months."

"These cattle are by far the most common reason why cattle herds suffer repeated TB breakdowns, not badgers. The government must heed this evidence and stop wasting time and resources on killing badgers to no effect," he added.