Most transition cow programs begin three weeks before calving.
Dr. Erminio Trevisi thinks they should begin much sooner.
During a recent Real Science Lecture Series webinar, the veterinarian and professor of animal science at the Catholic University of the Sacred Heart in Italy argued that dry-off is more than the end of one lactation. It is the first major biological event of the next one. The immune, metabolic and tissue remodeling responses triggered when milking stops may influence cow health and performance weeks later.
“The dry period is not a passive phase. It’s not a phase where the animals are simply resting. We have a lot of intensive reactions that sometimes are completely neglected,” Trevisi says.
That idea challenges one of the industry’s long-held assumptions. Dry-off has traditionally been viewed as a management event focused on stopping milk production and preventing mastitis. According to Trevisi, it deserves the same attention as calving because it marks the beginning of another transition.
More Than Stopping Milking
Trevisi argues that one of the biggest misconceptions about dry-off is thinking of it as a single event. In reality, cows are adapting to several major physiological and management changes at the same time.
During the first few days after dry-off, cows are simultaneously adapting to:
- Milk accumulation and mammary involution, as the udder begins remodeling for the next lactation.
- A new diet, requiring the rumen and metabolism to adjust to a different nutrient profile.
- Housing or social regrouping, which can increase behavioral and physiological stress.
- Advancing pregnancy, as fetal growth and nutrient demands continue to increase.
- Immune activation and tissue remodeling, as the mammary gland clears old cells and prepares to regenerate.
Stopping milking triggers the process, but the changes extend well beyond the udder. As milk accumulates, intramammary pressure increases and mammary tissue becomes more permeable. Immune cells migrate into the gland, inflammatory pathways activate and metabolism begins to shift as the cow prepares for the next lactation.
“Stopping milking is not only a physical challenge due to pressure inside the mammary gland. It is a complete reorganization of the body,” Trevisi says.
The timing is what makes the period so challenging. These events don’t happen one after another. They overlap, forcing the cow to adapt on multiple fronts at once. Trevisi argues it is this accumulation of biological and management stressors, rather than any single event, that makes dry-off a critical part of the transition period.
High-Producing Cows Face a Greater Challenge
One of Trevisi’s clearest findings is that cows producing more than about 15 kg of milk per day at dry-off mount a stronger inflammatory response than lower-producing cows.
Milk isn’t the problem. The biological response to high milk production is.
Greater milk accumulation increases pressure within the mammary gland, which may increase epithelial permeability and amplify inflammatory signaling. His research also found greater changes in inflammatory and metabolic biomarkers in higher-producing cows following dry-off.
“High-producing animals can be more susceptible to the other factors that increase the inflammatory challenge,” Trevisi says.
Rather than viewing milk yield as simply a production number, Trevisi suggests it may indicate how challenging dry-off will be for an individual cow.
Health at Dry-Off May Shape Health After Calving
Trevisi also presented evidence suggesting that what happens before dry-off doesn’t stay before dry-off.
In studies from his research group, clinically healthy cows with evidence of subclinical inflammation before dry-off continued to show inflammatory changes throughout the dry period and into early lactation. Those cows also produced less milk after calving than cows with healthier inflammatory profiles.
“Something present at the time of dry-off can trigger inflammation after calving,” he says.
The findings suggest dry-off does not reset the cow’s physiology. Instead, existing immunometabolic challenges may carry into the next lactation, affecting how successfully cows adapt during the transition period.
This raises an important question. Rather than assuming every cow enters the dry period on equal footing, should more attention be paid to identifying animals with underlying inflammatory or metabolic challenges before dry-off?
Lowering Milk Yield Isn’t the Only Goal
Trevisi also reviewed strategies designed to reduce milk production before dry-off, including feed restriction and changes in milking frequency.
His research showed that severe feed restriction successfully lowered milk yield, but it also increased fat mobilization, altered rumen fermentation and prolonged inflammatory responses after calving. Those unexpected findings have led his group to investigate more moderate nutritional approaches that reduce milk production without creating additional metabolic stress.
The broader message is that a successful dry-off strategy should be judged by more than how quickly milk production declines.
“No effect after dry-off does not mean no effect after the next calving,” Trevisi says.
In other words, management decisions made during the days leading up to dry-off should be evaluated by how well cows transition into the next lactation, not simply by what happens immediately after milking stops.
A Different Way to Think About Dry-Off
Nutrition, teat sealants, selective dry cow therapy and housing management will all remain important parts of successful dry cow programs. What may change is how we think about the period itself.
Rather than treating dry-off as the final step of one lactation, Trevisi believes it should be viewed as the first stage of the next transition period. The biological responses that begin when milking stops may influence inflammation, metabolic adaptation and performance weeks later.
“Dry-off could really be the inception of a sequence of challenges that can make it more difficult to organize a better transition period,” Trevisi says.
Instead of focusing only on milk production, udder health or the first few days after dry-off, we could judge success by what happens after the next calving. The first days of the dry period may prove to be just as important as the weeks that follow.
