This was despite disease outbreaks and challenges from disruption to pig flow during the pandemic that meant pigs spent more time on farm than usual.

According to data collected using the electronic medicine book (eMB), antibiotic use in 2020 reduced to 105 mg/PCU, compared with 110 mg/PCU in 2019 and 278 mg/PCU in 2015.

The data represents more than 95% of pigs slaughtered in the UK and continues the downward trend since recording started, although challenges with swine dysentery in 2019 and early 2020 temporarily halted progress.

The overall result is close to the target of 99 mg/PCU set by the UK pig industry, AHDB Sector Strategy Director for Pork Angela Christison said that in the context of a difficult year, achieving further reductions was a good result.

She said: “The industry understands how important responsible antibiotic use is and that is why there are tough targets and we work together towards them. The sector has delivered sustained reductions since recording began via eMB in 2015.

“This continued improvement, despite disruption to pig flow during the pandemic, is a credit to collaboration between producers, vets and the industry as a whole.”

Use of highest priority critically important antibiotics (HP-CIAs) remains at a very low level, although a slight increase from 0.04 mg/PCU to 0.05 mg/PCU has been recorded in 2020.

No colistin use has been reported in 2020.

HP-CIAs, as categorised by the European Medicines Agency (EMA), are the most important for human medical health and reductions in their use has been a focus for all UK farm animal sectors since stewardship efforts have stepped up.

Dr Mandy Nevel, AHDB’s Head of Animal Health & Welfare, said: “The EMA advice, which Pig Veterinary Society guidance supports, is that veterinary surgeons should prescribe a lower priority alternative to HP-CIAs unless there is no other option. This could explain why, despite the reducing trend overall, we are seeing an increase in use in some lower priority antibiotics such as neomycin.

“Alternatively, these could be short term adjustments as the industry accommodates the phasing out of therapeutic zinc oxide, which treats post-weaning diarrhoea in piglets.

“Either way, while the proportion of these antibiotics being used remains low, as does resistance reported through Government surveillance*, we must continue to monitor these trends and work to understand the reasons for changes in their use.”

Dr Nevel added that collaboration within the industry has been one of the success factors behind the reductions achieved.

Data is submitted to AHDB’s eMB, supported by a Red Tractor requirement for quarterly submission, before being analysed by AHDB and shared wider with the Pig Veterinary Society, National Pig Association, Pig Health and Welfare Council, RUMA, Veterinary Medicines Directorate and other stakeholders to generate a holistic view of antibiotic use in its sector.

The data allow industry to look at the more nuanced variations in individual antibiotic use to identify potential reductions.

Dr Nevel added: “The challenges in the industry during the past year highlight not just the importance of this cross-industry approach in our sustained drive for good stewardship, but also the need for antibiotics to safeguard pig welfare.”

Paul Thompson, Senior Vice President of the Pig Veterinary Society, said: “The eMB run by AHDB continues to provide the industry with data that is invaluable in disease control and at the same time ensures we continue to develop new and improved ways to use antibiotics responsibly.

“Future years will continue to pose challenges – for example, the scheduled withdrawal of zinc which is used to control diarrhoea in pigs. The eMB is a powerful tool which will allow us to monitor the impact of a range of interventions on antibiotic use and enable us to develop more sophisticated plans to control disease.

“We are at a stage where we have sufficient data to make informed assessments of the impacts which will allow us to help mitigate any detrimental changes.”

Professor Peter Borriello CB, chief executive of the Veterinary Medicines Directorate (VMD) of the Department for Food, Environment and Rural Affairs (Defra), said: “The 5% reduction in antibiotic use in pig farms between 2019 and 2020, alongside no colistin being used in 2020, is encouraging, and testament to the hard work of the veterinary and farming bodies in improving antibiotic stewardship.

"There is still work to be done, which the sector has already recognised in the target for a further 30% reduction between 2020 and 2024, but with the collaborative approach demonstrated to date I am confident that the sector will continue to rise to the challenge.”