Reducing Antibiotic Use Through On Farm Culture & Selective Treatment Of Clinical Mastitis

Mastitis is one of the biggest causes of antibiotic usage in dairy farming. Farmers and researchers in this field lab are trialing on-farm tests that detect which cases of infection involve bacteria that respond to antibiotic treatment, versus those that cure without the need for antibiotics.

The aim of the field lab is to reduce antibiotic usage in dairy farms through selective treatment of clinical mastitis using a new on farm culture test kit (MastDecide).

This new test system has previously had very little direct farmer testing. Participants in this field lab want to see whether it can be used by farmers as a practical and effective tool to significantly reduce antibiotic usage without affecting animal welfare and mastitis outcome parameters. 

While sensitivity and specificity of this test have recently been established under controlled conditions, there was previously no work published on the suitability of such a system in real farm conditions.

The group are also evaluating the general concept of on farm culture and selective treatment in more detail, comparing cows treated according to culture results with those treated conventionally with regards to their mastitis outcome parameters. 

The long-term plan is also to evaluate the time and cost investment by the farmer in using on farm testing and whether they are willing to adopt the technique long term. 

How it works

• Types of mastitis fit into two broad categories. Gram positive, cases with pathogens that require antibiotics and gram negative, cases that the cow will recover from without treatment.
• By using an on-farm test, farmers can see which cows have variants of mastitis which will cure without the need for treatment and which require antibiotics. 
• This means that dairy farmers can have a lot more targeted approach to antibiotic use on their farm. 
• This reduces antibiotic use and saves the cost of the drug and waste milked milk from treated cows.

Trial design

Farmers receive an incubator (partially subsidised) and are trained by their local vets who themselves receive a training session in the concept behind and use of the test kit. 

The farmers in the group then use the test kit on half of the mastitis cases in their herd and treat the other half conventionally. 
An accredited lab is carrying out routine culture on the samples and confirming the species by a mass spectrometry test (Maldi-Tof).  
Vets submit the details of the cases and electronic farm data on mastitis and milk quality to the researcher.
The researcher compares the on farm culture results with the external lab results and the blanket treated and cultured cases with regards to mastitis outcome parameters.

For further information on the background and methods of the trial please go to the Results & Reports section of the field lab page.

Interim results

Reducing antibiotics

Interim results from the field lab show that, for those farms where the conditions are appropriate for this treatment, on-farm tests reduce antibiotic use in infected animals by an average of 35%. If used on half the UK’s dairy farms this could lead to a yearly reduction of around 120,000 antibiotic doses.

Lower costs

On an average herd (250 animals) 31 cows would not need treatment. This means the average organic dairy farm could save around £2,200 by avoiding wasted milk lost from treated cows where milk cannot be sold, and £400 in antibiotic treatments, adding to savings of £2,600. Non-organic farms could save £600 by avoiding wasted milk and £400 in antibiotic treatments.