A cow can deliver a calf without assistance and spend less than an hour in active labor. Another can take nearly twice as long. Both may be recorded as normal calvings.
Dr. Jessica McArt, professor and dean of the College of Veterinary Medicine at Cornell University, and colleagues wanted to know whether that difference in labor might show up after calving. Using video from 95 multiparous Holstein cows, they measured active labor from the first visible abdominal press until the calf’s hips were expelled from the vulva.
What the Labor Duration Study Found
- Labor duration: 24 to 200 minutes, with a median of 65 minutes.
- Shorter vs. longer labor: Cows at the 20th percentile averaged about 45 minutes, compared with about 100 minutes at the 80th percentile.
- Postpartum response: Longer labor was associated with greater haptoglobin concentrations at 3 and 7 DIM.
- Calving difficulty: None of the cows required assistance.
- Study design: Researchers accounted for parity and characteristics of the original pen setting in their modeling.
Haptoglobin is an acute-phase protein that increases when inflammation is activated. Researchers use it as a marker of the intensity of the inflammatory response, including during the postpartum period in dairy cows.
“What I took away from this was the question: what can we do to help our herds reduce labor duration?” McArt says.
There are still some important pieces missing. Why did some cows take longer to calve? Did the longer labor itself contribute to the higher haptoglobin concentrations? The study wasn’t designed to answer those questions. It does, however, highlight something we know surprisingly little about on many dairies: how long cows actually spend in active labor.
Why Labor Duration Matters in Dairy Cows
Most dairy records tell us whether a cow needed help. They don’t necessarily tell us how long she was actively pushing.
That was one of the gaps McArt highlights in the study. Because the researchers had video footage, they could identify the beginning and end of active labor. On a commercial dairy, that information is rarely captured.
“We just know they’re moved and the calf comes out at some point and we know if we have to help them, but very little is happening with how long they actively push,” McArt explains.
McArt sees potential for technology to fill that gap. Machine-learning systems and video cameras could eventually identify the beginning and end of active labor without requiring someone to review hours of footage.
If labor duration becomes easier to capture, it could give veterinarians another variable to examine alongside calving ease, parity and postpartum outcomes.
Maternity Environment May Influence Labor Duration
The next question is what makes one labor longer than another.
The study doesn’t answer that, but McArt points toward the environment surrounding the cow. A maternity pen can be a busy place: people moving through, other cows entering and leaving, equipment operating and plenty of noise.
She notes that movement of cows into and out of maternity areas has been shown to increase labor duration.
That gives farms something practical to examine. How much activity does a cow experience while she is trying to calve? Are routine movements necessary at that moment, or could some be delayed?
McArt’s thinking extends beyond the cow herself.
“It’s not just a cow thing, it’s a human thing, it’s an animal thing,” she says.
Farms may not be able to eliminate every disturbance, but they can look at which activities around calving are necessary and which could be minimized.
What Happens After Calving?
The management discussion extends beyond labor itself. Once the calf is born, the cow has to begin eating and recovering while adapting to lactation.
Feed access is one area McArt raises as particularly important. Farms handle the immediate post-calving period differently. Some cows move quickly into a fresh pen; others remain in the maternity area for several hours or continue eating the close-up ration. Those decisions determine what the cow has access to during those early hours.
McArt’s observations from her inflammation work illustrate the potential difference:
“It is amazing, when you have a cow who calves in a tie stall with a bucket of fresh feed in front of her immediately, how much she will eat in eight hours.”
That observation points to a broader question around the hours immediately following calving: How quickly can cows get access to fresh feed and water, and how much does that early postpartum environment vary from farm to farm?
Cow comfort, appropriate maternity facilities, minimizing unnecessary stress and rapid access to feed and water after calving are all potential management considerations.
A Longer Labor Isn’t Automatically a Problem
The study doesn’t establish a cutoff at which normal labor becomes a problem. What it does show is that cows vary considerably in how long they spend in active labor, even when they ultimately deliver without assistance. That variation was associated with differences in haptoglobin after calving.
The next questions are more practical: Why do some cows take longer? How much of that variation can be influenced by management? And could reducing unnecessary prolongation of labor improve the cow’s recovery?
For now, labor duration may be worth thinking about as another piece of the calving record, rather than another reason to intervene.
