What inflammation can tell you about what’s happening inside the cow It’s no secret to most dairy producers that the transition period – spanning the three weeks before and after calving – is a challenging time in the cow’s production cycle.
The onset of lactation, combined with social, dietary and immune stressors, makes this period a risky window of time for the cow with higher probabilities of infections and metabolic disorders.
A successful transition sets the cow up for a successful lactation, and poor outcomes can put it at a disadvantage compared to its herdmates.
Cows with transition problems such as metabolic disorders or infections (e.g., metritis or mastitis) have lower projected milk yields for the lactation and a higher risk of leaving the herd compared to cows that have a healthy transition period.
One of the reasons a transition disorder is so disruptive is because a small initial problem can easily snowball. Contracting an infection during the fresh period increases a cow’s risk of developing ketosis, and having ketosis increases the risk of contracting an infection.
With this in mind, it is reasonable to expect that if we can prevent ketosis, then we can decrease the prevalence of infections during the transition period in a herd – and vice versa. Technologies available to monitor fresh cows may be a worthwhile investment if they allow producers to intervene for a cow before she develops a full-blown condition.
What can we monitor?
There are numerous biomarkers during the close-up period that can be used to predict problems during the fresh period. These include body condition, feed intake, blood ketone and calcium concentrations, markers of inflammation and oxidative stress, and measures of immune function. Let’s dig into the details on a few of these.
It is common knowledge that feed intake of many cows will drop before they calve, and recent studies have demonstrated that those declines are notably greater for cows that will have transition disorders. In some cases, depression in feed intake may occur weeks prior to other clinical signs of disease.
While it is not necessarily true that this magnified drop in intake is the cause of the subsequent problems, for the dairy producer, depressed feed intake could still serve as a warning signal for an impending problem. Given the growing amount of precision technology available, monitoring feed intake or time spent eating is becoming an achievable management goal for both large and small dairies.
Blood or urine ketones are already a common metric producers monitor when checking fresh cow health. Handheld devices that can be used to monitor blood ketones cowside are readily available at most drugstores and can be useful for detecting problem cows early.
In fact, some recent findings suggest that blood ketone concentrations above 0.8 mmol per L in the week before calving are linked to lower early lactation milk yield and higher risk of displaced abomasum and culling.
Dairy scientists are also currently investigating the relationship between inflammation and metabolism during the fresh period. Cows with high levels of inflammation during the transition period are more prone to disease and metabolic disorders during that time, and they often have lower milk production than cows with a lesser degree of inflammation.
In research settings, markers of inflammation such as haptoglobin (a protein produced by the liver during times of stress) and measurements of decreased immune function have shown promise as ways to identify problem cows. Unfortunately, it will be some time before these methods are convenient to implement on commercial farms.
Ultimately, we hope ongoing research will clarify whether behavioral changes (such as decreased feed intake) occur in the same subset of cows that show signs of inflammation and suboptimal metabolic function. If so, it may be possible to identify upcoming problems in cows with behavioral data alone.
What do we do next?
Preventing transition problems can increase lactation performance, and there are several tools currently available to monitor fresh cows. But even if we are able to identify cows that are on a path toward problems, how should we intervene?
One practice used on many dairies is the treatment of ketotic cows with propylene glycol. There is also evidence that giving cows propylene glycol before ketosis is detected can prevent it from developing.
Whether it is administered as a blanket treatment for fresh animals, as a preventative measure for high-risk cows or as a treatment for cows that are already experiencing ketosis, propylene glycol is a useful, inexpensive tool for managing ketones on dairies.
Don’t forget that ketosis is associated with other problems in fresh cows, so aggressively managing it has the potential to have big payoffs in the overall transition program.
There is growing evidence that poor vitamin E status is predictive of transition problems. Additionally, supplemental vitamin E has decreased the incidence of conditions ranging from mastitis to retained placenta in numerous transition cow studies.
Producers and nutritionists should be sure vitamin E is being included in the close-up diet at adequate levels, and even when it is, targeted use of injectable vitamin E for individual cows with low vitamin E status may be worth considering.
To summarize, while we may not be able to fully take advantage of recent research findings, there is a growing list of tools ready to help predict which cows are going to need support to transition successfully.
In our efforts to treat cows already struggling with transition disorders, let’s not overlook the potential of broad interventions to head off problems in some cows before they start. PD
Barry Bradford is a professor in the department of animal sciences and industry at Kansas State University.
Visit Kansas State University - diary metabolism group to learn more.
Gail Carpenter is a Ph.D. graduate student at Kansas State University.
