For many dairy farms and calf raisers, shipping calves across state lines, or even just a few hours down the road, has become the new norm. But as David Renaud, Ph.D., explained during a recent Heifer Academy webinar, the decisions made before, during and after transport can have serious impacts on calf health, growth and long-term productivity.
“Transport is more than a logistical step,” Renaud says. “It’s a pivotal control point for long-term health and performance.”
Renaud, a veterinarian and researcher at the University of Guelph, has spent years digging into how transport affects calf health, growth and disease. His research shows just how quickly stress can pile up and why the choices made before, during and after a calf hits the road really matter when it comes to raising strong, healthy animals.
The Weight of the Journey
Calves endure a unique combination of challenges during transport such as limited access to food and water, temperature swings, crowding and exposure to new pathogens. In one study of 175 calves transported for six, 12 or 16 hours, those on the longest trips showed more signs of dehydration, higher rates of diarrhea and respiratory disease and depleted energy reserves.
“Calves on the 16-hour trip stood longer during transit but needed more rest afterward,” Renaud notes. “They also avoided areas that resembled trailers, which suggests they experienced psychological stress, too.”
Why Age Matters
Age plays a major role in how well calves handle transport, according to Renaud. Calves moved at 11 days or older had fewer sick days and gained more weight compared to those shipped younger. In another study, mortality dropped from 6% to 3% when calves were transported at 28 days instead of 14. These older calves also needed less treatment and ended their feeding period at heavier weights.
“I think transporting at an older age is probably a good thing,” Renaud says. “But we still need more data to say exactly when that sweet spot is.”
Globally, there’s growing consensus around transport age. Canada requires calves to be at least eight days old for auction, while Europe mandates 14 days and is considering raising it to 35. Australia and New Zealand require calves to be four to six days old before transport.
Is Rest During Long Hauls Worth It?
To comply with new Canadian regulations, calves traveling more than 12 hours must receive a rest period. Renaud’s team studied the impact of this rule by comparing calves transported for 16 hours straight with those given an eight-hour rest stop that included two milk feedings.
Results were mixed. While rested calves, especially those 9 to 10 days old, showed some growth improvement, they also had slightly higher treatment rates for respiratory disease.
“Those extra transitions — load, unload, rest, then reload — can wear calves down,” Renaud says. “The next day, we saw more laying behavior, likely due to fatigue.”
Fueling Calves for the Road
One of the most impactful changes producers can make is to feed milk before transport. Calves that weren’t fed beforehand showed higher levels of non-esterified fatty acids (NEFAs), evidence that they were burning body fat to power through the journey.
“Basically, they’re pulling from their own body reserves, which isn’t ideal for a young calf,” Renaud explains.
In a follow-up study, milk-fed calves during a rest stop had better activity levels, fewer signs of illness, and no negative impact on growth when compared to calves fed electrolytes.
“Even in a stressful environment, feeding milk made a difference,” he says. “It’s a smart move. They need that energy.”
Health Checks Matter
The health status of a calf before it’s loaded onto the trailer plays a huge role in its outcome after arrival. In a study of more than 600 calves transported from British Columbia to Alberta, those with fever, umbilical infections, diarrhea or dullness were significantly more likely to need treatment, or die, at the calf raiser facility.
“I think it’s really, really important that we make sure calves are totally healthy and fit for transport,” Renaud says. “No fever, no infection and they should be bright and alert before they leave.”
Colostrum Is Still King
Renaud stresses that passive transfer remains one of the most important predictors of calf success. In a study of 1,000 calves arriving at a veal facility, those with poor colostrum absorption (under 10 g/L of IgG in blood) had a survival rate of 87%, compared to 97% in calves with IgG over 25 g/L.
“We talk a lot about colostrum for heifers, but even for male calves or crossbreds, it’s still absolutely critical,” Renaud adds. “Clean, high-quality colostrum fed early can make a huge difference.”
Don’t Overlook the Trailer Environment
Beyond distance and duration, the conditions inside the trailer can make or break a calf’s ability to cope. Poor ventilation, especially in sealed trailers during transitional weather, can lead to heat buildup and excess humidity, creating ideal conditions for respiratory disease.
“You may think you’re protecting the calf by sealing up the trailer, but you could be setting them up for pneumonia,” Renaud says. “Ventilation is probably a much bigger factor than we realize.”
Vaccines and Stacking Stressors
It’s common to vaccinate calves at birth or just before shipping, but Renaud says it’s worth rethinking that timing.
“There’s not a lot of data on how vaccines perform when calves are stressed,” he explains. “If you’re vaccinating right before or right after a long trip, there’s a chance the immune system won’t respond the way you want.”
Studies in feedlot cattle show that vaccines given at arrival aren’t always effective, and Renaud believes the same concern applies to newborn dairy calves.
“Stacking injections like vaccines, vitamins and antibiotics all at once just piles on the stress,” he adds. “If we want better immune protection, we might need to space those interventions out.”
Better Planning Means Better Outcomes
With more than 5 million dairy calves transported annually across North America, small changes in protocol can have a big impact. Renaud says producers should look at transportation not as a necessary evil but as a management tool.
Renaud’s tips for setting calves up for transport success include:
- Wait until calves are at least 10 to 14 days old before transporting
- Make sure calves receive high-quality colostrum early and adequately
- Feed a full milk meal before loading them on the truck
- Do a thorough health check. Only transport calves that are bright, alert and healthy
- Pay attention to ventilation, especially during seasonal transitions
- Avoid stacking multiple injections or vaccines around transport time
From colostrum quality to careful health checks and strategic feeding, every decision around transport matters. While not every challenge can be eliminated, producers who take a proactive, research-backed approach can significantly improve calf outcomes. As Renaud emphasizes, small, thoughtful changes made before the trailer doors close can set calves up for healthier starts, smoother transitions and stronger performance throughout their lives.
“Transport isn’t just a necessary step,” he adds. “It’s a management opportunity, and one that has a real impact on the future of the animal and the operation. With better preparation, we can give these calves the tools they need to handle that stress and thrive.”
Watch the full webinar with Dr. David Renaud here:
