Early detection and prompt effective treatment (EDPET) is a cornerstone of lameness management in dairy cattle and a key success factor within the AHDB Healthy Feet programme. However, the most important aspect of this approach is early detection. If cows are detected too late, when lameness is already obvious, the benefit of implementing prompt effective treatment is not realised. In turn, this can lead to a failure to see real progress in lameness prevalence which can lead to the farm team feeling demotivated and frustrated.
More than 20 years ago, O'Callaghan et al (2003) explored the link between changes in a cow's locomotion in response to pain, and the value of this as a method as a method for detecting foot lesions. This research was then expanded and standardised into what has become the AHDB 0–3 mobility scoring system. The descriptors for each category provide an objective measure against which to assess a cow while she's walking, with the ultimate goal of identifying a ‘cow that may benefit from treatment’.
Despite increasing awareness and focus on lameness over the past 20 years, it remains the biggest welfare challenge in the dairy industry. Its visible nature also makes it a considerable reputational risk. Understandably, it has been incorporated into assurance schemes as a welfare measure, however, this also creates a situation where a single assessment is attempting to be both a diagnostic screening tool and a measurement against which targets are set and, in some cases, penalties incurred. These two different ways of using mobility scoring create different goals in terms of sensitivity and specificity, which can create challenges when approaching mobility scoring on the farm.
Setting those challenges aside, going back to the roots of lameness detection means focusing on the cow level and using mobility scores for her direct benefit. There is significant value in using mobility scoring for monitoring patterns, evaluating responses to changes and also benchmarking. However, for an early detection system, the focus must always be on the individual cow: is she likely to benefit from treatment?
The Register of Mobility Scorers (RoMS) (AHDB, 2025) was established with the objective of standardising the training and assessment of mobility scorers to ensure those carrying out assessments for assurance schemes were appropriately trained and accredited. However, even where there is a high level of standardisation, a subjective measure will always be at risk of human bias, both conscious and unconscious. This is compounded by the fact that mobility is on a continuous spectrum and thus within each score category there will be a range of severity. Where those thresholds are set for the different score categories influences outcome.
Ultimately, many factors may influence the outcome of a mobility score on an individual farm. The most effective way to achieve results is to tailor EDPET to each farm based on the gold standard outcome: identifying not only lesions requiring treatment but also early lesions needing intervention. Linking hoof-trimming records with mobility score data is essential for this and provides a level of quality assurance, ensuring that mobility scoring is achieving its purpose: identifying cows that are likely to benefit from treatment.
When determining the success of lameness detection, it is important to consider the presence of lesions on the cow and identifying the type of lesions. For instance, detecting a sole ulcer may be seen as a positive outcome from EDPET, but it represents a missed opportunity as it should have been detected earlier at the bruising stage. On farms where robust EDPET protocols are in place alongside routine preventive trimming by a skilled trimmer, a target of <1' sole ulcers is realistic and achievable (Figure 1).
Despite the proven benefits of EDPET (Leach et al, 2012; Groenvelt et al, 2014; Thomas et al, 2016), it is still an underused tool on farms. It is one of the few actions that can be rolled out across every farm regardless of breed or management system. It also applies to all of the major lesions causing lameness on a farm (digital dermatitis, sole bruising/ulcer and white line disease). Time or financial pressures as well as lack of ‘buy-in’ to the benefits are barriers that must be overcome to ensure greater uptake to drive down lameness at a national level.
To combat some of the challenges mentioned there have been significant advances in technology and computational advancements of artificial intelligence (AI), with the creation of AI algorithms to create a lameness probability. A multitude of different methods have been assessed including accelerometers, weighing platforms, acoustic analysis, radar sensors and computer vision technology (Siachos et al, 2024). This has multiple benefits in terms of continuous rather than single-point monitoring and has reduced the time burden associated with lameness detection. It also removes bias from the decision-making process. The literature reports promising accuracies. However, the vast majority of studies use the gold standard outcome of a human-generated mobility score, with very few focusing on what should be considered the gold standard outcome: the detection of a lesion requiring treatment.
As technologies are explored further it will also enable further enhancement and refinement of treatment protocols and optimal thresholds for intervention. However, while that is still being developed, there remain significant opportunities on farms to work towards improved detection. As we move forward with increasing focus on further reducing lameness, we must never lose sight of who matters most: the cow.