How long cattle can legally be transported depends on where you are. In the United States, the limit is 28 consecutive hours before animals must be unloaded for feed, water, and rest. Canada allows up to 36 hours for adult cattle, while the European Union caps journeys at 29 hours with a mandatory rest break in the middle. Young calves face stricter limits in every jurisdiction.
U.S. Transport Limits Under the 28-Hour Law
The federal 28-Hour Law (49 U.S.C. 80502) is the main regulation governing livestock transport duration in the United States. Under this law, cattle cannot be confined in a vehicle or vessel for more than 28 consecutive hours without being unloaded for feeding, water, and rest. After unloading, animals must be given at least five hours of rest before the journey can resume.
Notably, the U.S. has no age-specific transport limits for young calves, making it an outlier among major cattle-producing countries. A multi-country regulatory comparison published in Royal Society Open Science found that Australia, Canada, the EU, and New Zealand all set separate, shorter limits for very young animals, while the U.S. applies the same 28-hour rule regardless of age.
Canadian and European Rules
Canada updated its Health of Animals Regulations to set a 36-hour maximum for adult cattle that can eat hay and grain. That’s the longest legal window among major Western jurisdictions. For calves 8 days old or younger, Canada restricts transport to a single trip of no more than 12 hours from the start of loading to the end of unloading. Older unweaned calves (roughly 9 days to 8 weeks of age) also face a 12-hour cap.
The European Union under Regulation 1/2005 allows cattle, sheep, and goats to travel up to 29 hours total: 14 hours of driving, then a mandatory 1-hour rest stop for water, followed by another 14 hours. After that, animals must be unloaded for a full 24-hour break before the journey continues. The EU also sets minimum age requirements: calves must be at least 10 days old for journeys under 8 hours and at least 14 days old for anything longer. Unweaned animals get a mandatory 1-hour rest stop after 9 hours, during which they must be offered liquid and, if necessary, fed. These rules do not apply to sea transport.
Australia has the strictest rules for very young stock. Calves 5 days old or younger can only be transported for 6 hours when heading to a calf-rearing facility. For adult cattle, Australia caps transport at 48 hours.
How Transport Duration Affects Body Weight
Cattle lose weight during transport, a phenomenon the industry calls “shrink.” This happens through a combination of dehydration, gut emptying, and metabolic stress. The losses add up quickly and have real economic consequences.
Data from the Alabama Cooperative Extension System shows how shrink increases with time on a moving truck:
- 8 hours: 5.5% body weight loss
- 16 hours: 7.9% body weight loss
- 24 hours: 8.9% body weight loss
For context, a 1,200-pound steer loses roughly 66 pounds after 8 hours on a truck and about 107 pounds after a full day. Standing in a dry lot without feed or water produces somewhat less shrink (3.3% at 8 hours, 6.6% at 24 hours), which highlights that the vibration, noise, and physical effort of balancing on a moving vehicle adds to the toll beyond simple food and water deprivation. Much of this early weight loss is from the gut emptying out and can be recovered relatively fast once cattle eat and drink again. But the longer the trip, the more the loss shifts toward actual tissue dehydration, which takes days to recover from.
Stress and Recovery After Long Hauls
Beyond weight loss, prolonged transport triggers a cascade of physiological stress responses. Cattle show elevated cortisol (the primary stress hormone) and higher levels of lactate, a marker of muscle fatigue, in the hours and days following transport. Inflammatory markers also spike. In one study comparing calves transported for 4 hours versus 15 hours without a rest stop, the longer-haul group showed significantly higher levels of acute-phase proteins, which are part of the body’s inflammatory response, at the time of unloading.
Rest stops do make a measurable difference. Calves given an 8-hour rest period midway through transport showed lower fatigue markers than calves hauled the same total distance without a break. The benefits were most apparent in the first few days after arrival, when rested calves showed better recovery trajectories. These findings are part of the biological rationale behind mandatory rest-stop regulations.
Recovery after transport is not instant. Stress hormones and inflammatory markers can remain elevated for 3 to 5 days post-arrival, depending on the length of the journey, the animal’s age, and whether it was conditioned to handling before the trip. Animals that had prior experience with human handling and loading facilities tended to show lower stress markers than animals encountering transport for the first time.
Heat and Humidity Change Everything
Legal time limits assume reasonable weather conditions. Heat stress can make otherwise legal transport durations dangerous or deadly. The Temperature Humidity Index (THI) is the standard tool for assessing risk. When THI reaches 72 or higher, handling and transport should be reconsidered. When the heat index hits 100°F or above, transporting cattle poses a significant health risk and should be avoided entirely.
Cattle generate substantial body heat, especially when packed together in a trailer, and they cool themselves far less efficiently than humans do. A journey that’s perfectly safe in cool morning air can become life-threatening by midafternoon on a humid summer day. Best practice is to transport during early morning hours and monitor weather forecasts closely. If moderate to severe heat-humidity conditions are expected, postponing the trip until cooler weather arrives is the safest option, regardless of what the legal time limits technically allow.
Summary of Limits by Country
- United States: 28 hours for all cattle, no age-specific calf limits
- Canada: 36 hours for adult cattle; 12 hours for calves under 8 weeks
- European Union: 29 hours (with a 1-hour mid-journey break) for adult cattle; calves must be at least 10-14 days old depending on journey length
- Australia: 48 hours for adult cattle; 6 hours for calves 5 days or younger
- New Zealand: 12 hours for calves 14 days or younger
These are legal maximums, not recommendations. Shorter transport times consistently produce better welfare outcomes, less weight loss, and faster recovery. When planning cattle transport, the practical goal is to keep the journey as short as conditions allow, not to push up against the legal ceiling.