“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.

The time it takes for the animal to return to pre-transport immune levels is also worth noting. It can take up to six days after transport for the immune system to return to normal. In terms of the physiological responses your cattle undergo, the increased blood levels of free fatty acids, urea, creatine kinase and ‚-hydroxybutryate require time to return to normal. In long-distance transport the recovery time can be as long as five days due to the disruption of food and water consumption. This is something to consider when your bulls are being hauled to different events around the country. If your bull is not performing at his peak, it can be due to a depressed immune system or other physiological disruptions from the transportation.
Cattle, when compared to other large animals such as horses, have higher cortisol sensitivity. This aspect comes into effect when reproduction is in question. If you have just transported a load of females from, say the feed yard, and you want to AI them, it is best to wait until they have settled down and acclimate to their surroundings. The less stress they are under, the higher their conception rates will be. Also, if you are hauling your females to have reproductive work done, the stress can cause the females not to take.

It is important to note that there are two phases of stress associated with shipping. The first phase is considered the “perception of events” in which the cattle go through the process of being loaded into the trailer. This can be amplified if poor handling techniques are used and the level of anxiety is increased. The second phase is the transportation itself. This is the stress of standing for long periods of time, trying to stay balanced, the novelty of the surroundings, weather, etc. These two stressors together lead to the above mentioned impacts of transporting cattle.

Unfortunately, science has yet to find any real remedies to the problems associated with transportation stress. There have been attempts to use electrolyte supplementation during transport which has been shown to decrease dehydration. However, when hauling calves it is detrimental to give them access to cold water mid-trip because it negatively affects their electrolyte balance. Having your animals in good nutritional condition and properly vaccinated will help with their coping abilities. Additionally, if you’re hauling your bulls to events, if you get them there a few days prior to the event you will give them more time to recover from the shipping stress. This is usually not possible given the scheduling of most of the events; however, if it is possible it should be utilized.

Another method to improve the trip for the bulls is having a good driver and selecting the best routes to drive. Cattle do much better on open roads than they do in suburban areas or country roads where there is a lot of stop-and-go traffic or bumpy roads. Your driver should have experience hauling livestock and should take care when braking and making turns. This seems like common sense, but there are drivers who handle their cargo rougher than they should. The easier the ride is, the less muscle fatigue your bulls will undergo and that should help their performance.

When you hear about the bulls that are considered the best, it is usually noted that these bulls haul well. There certainly is truth to that. Every animal is different and some bulls will handle travel better than others will. These bulls will habituate to the routine of loading and traveling and perform at their peak like nothing ever happened. Other bulls will suffer from transportation stress and put on a poor performance. The best bet is to alleviate as much stress as possible during the loading and driving as possible and make sure they’re healthy before the trip.

Natasha Romero is a student at Texas A&M who has extensively studied the science of bucking bulls for the past seven years. She recently completed her Master's in Behavioral Science and Genetics and has started on her Ph.D. in Genetics, all with an emphasis on how it applies to the bucking bull industry. Natasha also received her undergraduate degree from Texas A&M in Animal Science with an an emphasis on beef cattle.