What Is EBVM & How Can It Be Applied To Farming?
As farm vets, it is important to try and take an evidence-based approach to our clinical decisions.
For example, a new calf vaccination protocol for a group of 50 calves was introduced and then antibiotic use for calf pneumonia was compared from the current year to the previous year. Following the new vaccine protocol, 2 calves still needed treating whereas last year, 30% of calves needed treatment. The vet (who was expecting it to work) might assume that the protocol is great whereas the farmer (who is less convinced by vaccination) might not accept anything less than 100% success as an outcome.
This tendency to look for patterns and make assumptions based on previous experiences is known as ‘bias’ and is a natural human tendency but how can we get over this to come up with the best answer?
A Stepwise Approach To Using EBVM
- Ask – what is the specific question you are trying to answer?
- Acquire – what evidence is available that can answer the question?
- Appraise – what is the quality of the evidence (anecdote vs RCT), can we believe the source?
- Apply – implement a change on-farm based on your findings.
- Audit – review the outcome at specified time intervals to monitor whether the change is having a positive effect.
(Adapted from Hyde and Remnant, 2016)
Examples Of EBVM In Farming
- AHDB mastitis control plan.
- Dairy Industry Standard Locomotion Scoring.
- TB Advisory Service (TBAS).
Just because there is an absence of evidence, it does not mean that a treatment does not work. I am not suggesting that EBVM should replace experience but rather that it can be used as a tool to improve knowledge and help to problem solve on-farm.
Hierarchy Of Evidence: Calf Pneumonia Vaccine Example
A Word Of Caution!
Beware the internet. It is very tempting for farmers (and vets) to Google an answer to a problem, but there is so much information (good and bad) out there that it is important not to believe anything without first scrutinising the source. Farming forums are a great way of creating an online community, but it’s easy for everyone who comments to appear to be an expert.