One in four dairy cows develops metritis. It’s one of the most common and costly diseases in the postpartum period.
But Caio Figueiredo, assistant professor at the College of Veterinary Medicine of Washington State University, raises the following uncomfortable question:
What if we’re not actually defining metritis correctly in the first place?
Because if the definition is off, everything downstream — diagnosis, treatment, antimicrobial use — follows it.
The Cracks Start at Diagnosis
In practice, metritis is diagnosed visually, using vaginal discharge scoring. It’s simple, fast and scalable across herds. Cows are generally scored on a scale of 1 to 5. The issue lies not within how to score cows, but in which scores define metritis.
“There isn’t a clear consensus of what discharge, on the clinical level, distinguishes a cow with metritis or not,” Figueiredo explains.
That lack of agreement directly shapes which cows get treated. So before we even talk about treatment protocols, we’re already dealing with a moving target.
Most scoring systems eventually funnel into two categories that matter clinically:
- VD4: Purulent discharge
- VD5: Fetid, watery, red-brown discharge
Both are commonly labeled “metritis” and both are commonly treated.
But they don’t look the same — and the data suggests they don’t behave the same either.
“Are these two conditions metritis? Should we treat both, or just one?” Figueiredo asks.
Despite the uncertainty, most dairies don’t differentiate, treating both VD4 and VD5 cows with antibiotics.
“Only a very selected group treat exclusively VD5 cows. The remaining dairies treat both conditions,” Figueiredo explains, referencing a survey of 45 dairies in California.
VD5 Looks Like a Different Disease
When you step back and look across studies, a consistent signal starts to emerge:
“There is some evidence that those groups are not necessarily the same,” Figueiredo states.
That difference becomes much harder to ignore once you look beyond the discharge itself.
Start with inflammation, which isn’t just a uterine issue.
“VD5 cows have greater levels of inflammation compared to those with purulent discharge (VD4),” Figueiredo says. “Those VD5 cows have greater systemic inflammation as well.”
At the microbial level, the pattern holds. A 2024 study looked at the uterine microbiome to investigate the differences between VD5 cows and all others.
“Only cows with vaginal discharge score 5 have greater bacterial count compared to the other discharges,” Figueiredo explains.
These animals had greater overall bacterial counts, as well as increased Fusobacterium, Porphyromonas and Bacteroides counts compared to lower-scoring cows. And when you zoom out to the whole animal, the separation becomes even clearer.
In unpublished data from Figueiredo’s lab, VD5 cows show:
- Higher acute phase proteins (e.g., haptoglobin) postpartum
- Worse liver function indicators (↓ albumin, ↑ bilirubin, ↓ cholesterol)
- Altered metabolic profiles at diagnosis
- Reduced rumination and activity during peak risk windows
These results suggest this is not just a discharge difference, but a systemic disease state.
Performance Consequences
The biological differences translate directly into outcomes.
In large multi-herd datasets VD5 cows had noticeably impaired performance:
- Milk production: Up to 1,000 kg less milk over 300 DIM
- Reproduction:
- Lower likelihood of resuming cyclicity
- Reduced probability of receiving first AI
- Lower pregnancy rates by 300 DIM
- Survival:
- Higher risk of culling
- Faster removal from the herd
By contrast, VD4 cows were indistinguishable from lower score cows across many of these same parameters.
What Is VD4?
According to Figueiredo, if VD5 represents a true systemic disease, VD4 may represent something else — perhaps a milder, localized or even transient condition.
Across multiple datasets, VD4 cows perform similarly to their lower-scored herd mates.
Which raises a critical question: Are we treating cows that don’t actually need treatment?
The Economic Reality of Treating VD4 Cows
In the U.S. alone there are ~9.5 million dairy cows and a ~25% VD4 and ~25% VD5 incidence. That puts millions of cows into each category annually.
If both groups are treated:
- Total antimicrobial treatment costs can exceed $500 million annually
If VD4 cows are excluded from treatment:
- Potential savings approach $270 million per year
This difference in cost doesn’t account for labor, any effects of handling stress or the downstream impacts of antimicrobial use.
Why This Matters More Than It Seems
This isn’t just a classification issue. It touches multiple pressure points:
Antimicrobial Stewardship
Metritis is a leading driver of antibiotic use. Refining treatment criteria is one of the fastest ways to reduce unnecessary exposure.
Economic Efficiency
Treating cows that don’t benefit is pure inefficiency at scale.
Public Trust
Consumer concern around antimicrobial use continues to grow. Precision matters.
From Visual Diagnosis to Biological Precision
The takeaway isn’t to stop treating metritis, but to start treating it more precisely.
Right now, decisions are largely driven by what we can see. But the evidence suggests what we see doesn’t always reflect what’s happening biologically.
A more practical, data-aligned framework could look like:
- VD5 → clear systemic disease → treat
- VD4 → uncertain or mild → monitor, refine or selectively treat
This shift moves us away from a purely visual diagnosis model.
“We’re going to have to look deeper into the biology and then come back to the real-life problem,” Figueiredo says.
That means integrating:
- Immune and inflammatory markers
- Microbiome makeup
- Metabolic and behavioral signals
The goal is straightforward: Align diagnosis with biology, not just appearance.
Ultimately, VD4 and VD5 cows don’t share the same biology, the same risk or the same consequences. One behaves like a mild or localized condition while the other is a true systemic disease with measurable impacts on performance and survival.
Treating them the same way is inefficient and outdated.
The future of metritis management isn’t about treating more cows, it’s about treating the right ones.
