Calf oral antibiotic use doubles as industry targets 10% cut

Oral antibiotic use in calves has more than doubled in a year, putting fresh pressure on dairy farms to cut antimicrobial use and prompting calls to focus on vaccination as a practical solution.

New RUMA figures show calf oral antibiotic sales rose from 1.92 mg/kg defined daily dose for animals (DDDvet) to 4.03 mg/kg DDDvet in 2024.

In response, the industry body has introduced a new target to reduce calf oral antibiotic use by 10% year on year.

At the same time, the latest Kingshay data — covering 967 dairy herds across 136 veterinary practices — show overall antimicrobial use continues to fall.

Average usage dropped to 12.2 mg/kg PCU in 2025, down from 12.7 mg/kg in 2024 and 15.7 mg/kg in 2020.

However, antibiotic use remains concentrated within a smaller group of farms.

Herds in the highest quartile for antibiotic use accounted for 50% of total antibiotics used.

Within those higher-using herds, oral products — often administered to calves for respiratory disease and scour — made up 13% of total use.

While Kingshay data showed calf oral antibiotic usage fell from 1.38 mg/kg PCU to 1.05 mg/kg PCU between 2024 and 2025, the differing datasets measure separate indicators, underlining that calf oral treatments remain a key focus for the sector.

Emma Puddy, Kingshay farm services specialist and report co-author, said the use of oral antibiotics in calves can significantly inflate a farm’s overall antimicrobial figures.

“If you use oral antibiotics within calves, you will see that your usage is significantly higher than maybe the group average,” she said.

“Oral antibiotics tend to really increase your overall antimicrobial usage.”

She explained that injectable treatments are typically used for individual animals, whereas oral products are often administered to whole pens when disease risk increases — driving up total mg/kg metrics.

High antimicrobial usage can affect benchmarking performance and place farms under greater scrutiny from supply chains and assurance schemes.

Kingshay training consultant and vet Michael Head said reducing usage begins with understanding disease incidence through a robust herd health plan.

“Effective vaccination strategies form part of this because people can tend to reach for antibiotics, but the benefits of strong immunity, genetic advances and good nutrition mean cattle are better able to resist disease and, in turn, reduce the need for antimicrobials,” he said.

Despite this, AHDB vaccine data show fewer than 50% of calves are vaccinated against respiratory disease, while only around a quarter of producers vaccinate against calf scour.

Mr Head said newer vaccines targeting cryptosporidiosis and Mycoplasma bovis could help shift the dial.

“Their use is certainly increasing at pace, and I’m already hearing farmers recommending the use of vaccines to other farmers,” he said.

He also warned that calf disease has lasting consequences.

“Calf diseases have significant onward consequences with regard to the future health of those animals, their longevity and their disease resistance,” he said.

Dr Kat Baxter Smith, a vet at MSD Animal Health, said the findings highlight vaccination and management changes as a practical opportunity for farms seeking to reduce antimicrobial figures.

“Respiratory disease and scours remain two of the most common reasons antibiotics are used in young calves,” she said.

“By tackling these challenges earlier through vaccination and good management, farmers can significantly reduce the need for antimicrobial intervention.”

She noted that scours caused by cryptosporidiosis can be difficult to manage and pointed to reports of resistance to paromomycin in E. coli K99.

Vaccination, combined with good housing, ventilation and colostrum management, can reduce disease pressure and support better lifetime performance, resilience and productivity.

Farmers are being encouraged to review youngstock health plans with their vet ahead of the next calving period, particularly where oral antibiotics are routinely used in group treatments.