“Even with the great improvements made to all methods of shipping, transport is still considered one of the most stressful events that cattle will undergo during their lives.” This is a direct quote from a review on cattle transport conducted by J.C. Swanson and J. Morrow-Tesch taken from the Journal of Animal Science 2001. Shipping stress is of major importance in both the beef industry and the dairy industry. It has yet to be determined, through scientific study, the effects of shipping on bucking stock. However, the research conducted in other cattle industries is worth mentioning and has implications for our sport. T.G. Knowles made an observation that “concern for the welfare of cattle during and after transport generally increases with their economic value.” Given the value of rodeo stock today, it is safe to say that dealing with transportation stress is of the utmost importance.
Transportation stress has been implicated in morbidity and mortality rates in addition to affecting physiological, immune and behavioral responses. Transportation stress also affects reproduction and feed and water intake. Unfortunately, due to the many variables affecting individual animals it has been difficult to gather any concrete information regarding shipping stress and direct remedies for it. Some of the factors influencing the amount of stress cattle undergo include, but are not limited to, age, gender, breed, pre-transport handling, nutritional status, weather, novelty, food and water deprivation, driver experience and stocking densities.

Due to the fact that as cattle mature they respond better to stress, the effects of transportation are more noticeable in calves. Calves are not typically hauled as frequently as bulls; however, there are almost always lots of calves at the many different sales we attend. Calves are due special mention when it comes to transport. Scientific literature typically defines calves as cattle less than six months of age. For that reason I will be using the same definition.

Calves, unlike mature cattle, tend to lie down during transport. Therefore, it is important that there is bedding (such as wood shavings) provided. Calves can spend up to 42 percent of the time lying down during transport which is beneficial to them because it decreases the muscle fatigue that accompanies shipping. Keeping this in mind it is also important to monitor the stocking densities of trailered calves because they require enough space to lie down. Calves also experience a greater immune response to transport which leads to higher morbidity.

The physiological responses of transportation are caused by the stress the cattle undergo. The body temperature increases, the heart and respiration rates increase, and the activation of the hypothalamic-pituitary-adrenal axis (HPA) are all caused by this stress. The HPA causes increases in cortisol, a primary stress hormone, and glucose concentrations. Another physiological response is muscle fatigue due to standing. When the muscles become tired, they release the enzyme creatine kinase (CK) into the blood resulting in higher blood CK values. These values increase as the duration of the journey increases.

The immune system is also affected when cattle are transported. The risk of immunosuppression is greater in calves than it is in mature cattle. However, there are still studies that show the older cattle have immune responses to transport. This is important when you think about a highly stressed animal and the increased chance of sickness. Stress can lead to the shedding of cells from the lining of the intestine that can lead to extra bacteria (such as that responsible for shipping fever) to be excreted in the feces. If animals are hauled long distances they become more susceptible to shipping fever and diarrhea. Diarrhea can lead to increased dehydration which compounds the sickness and affects performance.

Another interesting aspect of transportation stress is that the duration of the trip may have less to do with the effects of stress the animal experiences. On a physiological basis, most of the reactions that occur in the body take place in the first 30 to 60 minutes of transport. After this point the reactions tend to level off for the remainder of the trip. So when you think about it, hauling your bulls to an event an hour away can actually cause as much stress as hauling them to the next state. This is not taking into consideration the muscle fatigue associated with longer trips, but it does account for many other physiological and immunological responses associated with transportation.