Large cattle herds are significantly more likely to suffer bovine TB outbreaks than smaller herds, a new study has concluded.
Researchers from the University of Exeter said their findings showed ’intensive farming practices’ increased the likelihood of cattle contracting bovine TB.
They also liked bTB risk to farming practices like the amount of maize grown, the use of silage and even landscape features like hedgerows.
The study, funded by BBSRC and published online here in the Royal Society journal Biological Letters on Wednesday, analysed data from 503 farms which had suffered a TB breakdown alongside 808 control farms in areas of high TB risk.
Key findings included:
Dr Fiona Mathews, Associate Professor in Mammalian Biology, who led the study, said: “TB is absolutely devastating for farming, and it’s essential that workable solutions are found.
"In the worst hit areas, farms are frequently affected over and over again with crippling consequences.
"If lower intensity production means better animal health, it offers a sustainable long-term strategy in high risk areas.”
The researchers said the last few decades had seen radical changes in farming practices, with half of British dairy farmers have gone out of business since 2002.
Those that remain have larger herds and greater productivity: average herd size increased from 75 animals in 1996 to 133 in 2014 (a rise of 77per cent). Meanwhile average annual milk yield has increased from 5,775 litres per cow in 1995 to 7,535l per cow in 2013 (a rise of 27 per cent).
Dr Mathews said: “This is the first large-scale study to link a range of landscape-scale habitat features and farming practices with bTB.
"All of the effects we have found are additive, so changing several linked aspects of the farming system could potentially make a big difference.
"Farmers are already aware that biosecurity in the farmyard can help reduce the risk of bTB in cattle.
"We have now shown that wider environmental management is also important. By finding out more about these links, we hope that we can help eradicate this terrible disease.”