Moving young calves from one facility to another can be a tough task for workers, and it’s even more difficult for the animals being moved.
On many dairy farms, calves are transported to heifer housing on or near the farm, but in some cases, young calves are hauled quite a distance to a heifer-rearing facility. Bull calves routinely leave the dairy farm at a young age and are transported to another farm where they are raised for veal or dairy beef.
The combination of young age, insufficient immunity, handling and transportation stress and co-mingling leads to higher disease incidence, impaired overall health status and higher use of antibiotics. Many of the health issues that show up in replacement heifers and veal or feeder calves at their new location trace back to early care on the dairy farm.
Independent dairy researcher Dr. Francesca Marcato discusses the challenges associated with transporting young calves. The most important factor is that most young animals are moved prior to developing a fully functional immune system.
“Colostrum is a critical source of antibody protection and nutrition for newborn calves,” said Marcato. “When calves don’t get enough immunoglobulin, especially IgG from colostrum, they experience failure of passive transfer immunity.” Colostrum with IgG below 10 g/L is likely to result in poor passive transfer and increased risk of disease.
Older cows have been exposed to more pathogenic agents, which affect IgG blood levels, and their colostrum may offer more protection via passive transfer.
According to Marcato, 12% to 42% of calves enter the veal or dairy beef industry with failure of passive immunity due to low quality or insufficient colostrum. “This is a major concern because these animals are more prone to getting infectious diseases,” she said. “They have a higher morbidity and mortality rate.”
Marcato cited research showing that calves arriving at a veal farm with an IgG level below 7.5 g/L were at the highest risk of requiring antimicrobial treatment.
One calf transport study showed a strong positive relationship between the amount of IgG initially consumed and maintained up to 10 weeks post-transport. “The more IgG the calf drinks, the more they get in the blood,” said Marcato. “The more IgG serum in the cow, the more IgG the calf has in its blood.”
Another study showed that calves with higher IgG levels had a lower chance of future treatment with antibiotics or other medications.
In some cases, young calves are gathered from different source farms and mixed together in the trailer where they are exposed to a number of different pathogens. Marcato said this practice contributes to high disease susceptibility.
Keeping calves healthy during and after transportation begins with calf management on the farm, especially the initial environmental conditions and care a newborn calf receives. Navel treatment immediately after birth is a critical factor in future calf health. Umbilical inflammation is a problem related to management on the dairy farm, and in referencing this issue, Marcato cited recent research comparing navel inflammation in bull and heifer calves. The study found bull calves had higher incidence of navel inflammation, likely due to inadequate navel dipping at birth.
“This is a problem because bull calves have an enlarged navel on arrival at the veal farm,” said Marcato. “The infection can spread to other parts of the body and they are at greater risk for early mortality. It’s important to prevent this condition by monitoring hygiene on the dairy farm and carefully dipping navels in disinfectant solution immediately after birth.”
One study showed calves from first calf heifers had the lowest body weights during the first week after birth and on the day prior to transport compared to calves born of multiple parity cows. There’s also a tendency for bull calves of first-time calvers to have a lower carcass weight compared to multiple parity cows. This is likely due to competition for nutrients between the still-growing heifer and her pregnant uterus during late gestation.
Age at transport and management upon arrival on the next farm are also significant factors in future calf health. Although not always practical, transporting calves after they’ve gained some immunity is preferable. Studies showed that calves transported at 28 days of age were more robust and had a higher carcass weight.
Marcato outlined three major challenges to address when planning transportation: nutrition prior to transport, how animals are transported (type of vehicle, climatic conditions) and duration of transport.
“It’s important that calves have a good start on the dairy farm,” she said. “Feed good quality colostrum, check for good navel hygiene and transport at an older age if possible.”
A variety of factors affect the health of animals during transport, and the key is to minimize stressors during a potentially challenging journey. The truck and/or trailer should be in good working condition to decrease the risk of breakdown. Inspect the trailer for sharp edges or broken parts that can cause injury. The trailer should be cleaned and disinfected prior to use, and filled with clean, unused bedding.
Calves with obvious signs of illness such as runny nose, fever or lethargy should not be transported until they have received appropriate veterinary care and are cleared for transport.
Because calves will be exposed to new and/or different pathogens that increase disease susceptibility, it’s important to minimize mixing and co-mingling prior to transport. Reduce unnecessary loading and unloading procedures to maintain minimal stress. Watch the behavior of calf handlers both on the farm and at the destination to ensure their actions don’t cause additional stress to calves.
During high temperatures, sawdust bedding will help animals dissipate heat. In low temperatures, a deep layer of straw helps to maintain body temperature.
Pay attention to stocking density in the transportation vehicle. Overstocking may mean animals can’t lay down, while low stocking density can result in animals being tossed around and injured. Drivers should avoid rapid acceleration, hard cornering and abrupt braking.
The optimal temperature for transportation is between 60º and 77º F. In higher temperatures, calves are prone to heat stress, and below 40º, calves are prone to cold stress.
Upon arrival at the next farm, calves should be housed according to risk, with a sick pen available for calves that require extra attention. Incoming calves should not be co-mingled with older calves without a quarantine period as advised by the farm veterinarian. Categorize calves by size and weight and/or age and feed a warm, high-energy meal immediately after transportation.
Young calves can be successfully moved without the risk of disease if the dairy farm practices appropriate husbandry. Increased communication and cooperation between the dairy farm and the veal or feeder side can benefit all parties involved.
by Sally Colby