The title may seem a little contradictory. Surely welfare targets help create better welfare outcomes?
We can start off with the concept of Goodhart’s Law, often brought up in economic and social policy circles.
Goodhart’s Law is often explained using the quote from anthropologist Marilyn Strathern: “When a measure becomes a target, it ceases to be a good measure.”
The economist Charles Goodhart’s original wording was more technical, but the message was similar: “Any observed statistical regularity will tend to collapse once pressure is placed upon it for control purposes.”
What has this got to do with dairy welfare? There is absolutely no intention to suggest anyone acts to corrupt welfare outcomes, but the concern is that well-meaning welfare targets may have unintended consequences which departs from the original objective.
The principle of seeking low lameness prevalence and fewer cows at the extremes of the BCS scale is understandable, but measuring at a whole-herd level could end up rewarding younger herds, rather than helping breed more resilient cows.
Prevalence, metabolic extremes and longevity
Lowering lameness prevalence in dairy cows is an aspiration that everyone can agree on, as is reducing the number of cows at the thinner and fatter extremes of the (Body Condition Score) BCS distribution, which may be at greater risk of disease and reproductive problems. Reducing avoidable or involuntary culling is another understandable goal.
A model by von Soosten et al. (2020) estimated that cows completing five to eight lactations could have an emission intensity per kilogram of milk up to 40% lower than cows leaving the herd after their first lactation. Much of this benefit came from diluting the emissions associated with the non-productive calf and heifer-rearing period across more lifetime milk.
Good targets can create the wrong incentive
The dairy cow is an extreme metabolic athlete, unrivalled in nature. The energy demand associated with milk synthesis has been compared with a human running multiple marathons each day, sustained across much of lactation (all whilst obtaining and maintaining a pregnancy).
CattleEye is able to capture consistent, objective and frequent data on mobility and BCS, allowing the prevalence of lameness and extremes of BCS to be explored across lactations. The pattern seen among the 3,956 cows in the graphs below is representative of patterns seen repeatedly across herds, geographies and systems. Age is associated with an increasing prevalence of metabolic dysfunction in other species, and the dairy cow is no exception. Lameness prevalence and BCS extremes rise predictably with lactation.
If we only look at prevalence of lameness and extreme BCS on an overall basis, then such targets may reward younger herds. This may also be at odds with welfare and sustainability aspirations if we seek to reduce avoidable culling and maintain a low replacement rate.
Finding solutions
As we know, there is no point talking about a problem without trying to find solutions.
One potential solution is to benchmark prevalence separately within each lactation or to age-standardise the whole-herd result against a common lactation profile. Measures of incidence, duration, recovery and recurrence may also provide more information than prevalence alone.
My personal interest is in better understanding the fundamental reasons behind the metabolic pressures of lactation, particularly around mitochondrial mechanisms, which are central to understanding metabolic disease in other species. With the dairy cow being the most metabolically impressive animal we know, it would seem important to consider these mechanisms. If we want cows that remain healthy and productive for multiple lactations, then a better understanding of the biology is necessary.
Data from agtech like CattleEye, wearables, milk analysis and so on could be utilised to better identify metabolic resilience.
CattleEye is already developing a new mobility trait via a joint research project with the Council on Dairy Cattle Breeding (CDCB) and the University of Minnesota. Preliminary analysis indicates that the mobility phenotype is meaningfully heritable, suggesting that it could contribute to future genetic strategies for reducing lameness and breeding more resilient cows. It is a good example of the synergy of combining large datasets with genetic strategy. Other sources, like fatty acid profiles of milk (reflecting metabolic partitioning), wearable data on rumination and eating, and BCS dynamics, may provide additive information to help develop further resilience traits.
Agtech, adoption, implementation and management bottlenecks
There is a valid argument that basic management bottlenecks remain when controlling the factors which influence lameness, BCS and other dairy cow disorders. Several agtech tools have met adoption barriers and there is a valid debate about funding priorities and adoption success.
There is no doubt that the first investment should be in the basics - footbath consistency, cow comfort, stocking density, lying time, transition nutrition, body condition control, trimming routines, staff training.
However, in the manufacturing industry, defects are wasteful, and root cause analyses are often undertaken to identify why defects occur. There could be a parallel in dairy cows. We have bred cows for centuries for milk, without fully understanding metabolism, resilience and longevity. Some cows may appear high-performing but metabolically fragile, which may become evident as BCS loss, lameness, poor fertility, disease or early culling. The large datasets generated by agtech, when combined with genomics, may help identify biological vulnerabilities and more metabolically resilient phenotypes.
Harnessing this expanding volume of novel data could help us breed and manage cows that remain healthy and productive for longer, reducing prevalence while maintaining or increasing the herd’s age profile.
The dairy cow is on a continuous escalator of increasing milk production and the associated metabolic challenges. Welfare targets may therefore need to adapt to capture genuine resilience as those challenges continue to increase… otherwise, they may unintentionally reward younger herds.
