During the recent Cattle Transportation Symposium in Fort Collins, Colo., Lisa Pederson, beef quality assurance specialist at North Dakota State University Extension, noted that about 125,000 finished cattle are on the road every day in the United States. And that is just finished cattle. Add in all the calves and feeder cattle shipped to markets, to other farms or to new pastures, and the total is likely close to 400,000 per day.
All that loading, unloading and time on the road create potential for injuries (to cattle or handlers), stress and economic losses. Veterinarians, though, are well-positioned to help their clients develop practices that minimize the risk of problems.
Also at the symposium, University of Tennessee professor emeritus Clyde Lane, PhD, pointed out that for many in the general public, their only exposure to livestock production occurs when they see animals being transported on roadways. If they see cattle confined in a broken-down trailer on a hot day or, even worse, injured cattle resulting from a preventable accident, their perception of animal agriculture is likely to become more negative.
Assessing transportation stress
Farmers, ranchers and veterinarians have long known that transportation can induce stress in cattle and have adopted practices intended to minimize that stress. Information is limited, though, on the effects of specific stressors, the range of variables involved or even which types of practices are used in shipping cattle.
During the symposium, Karen Schwartzkopf-Genswein, PhD, a research scientist with Agriculture and Agri-Food Canada outlined how modern research methods can provide better understanding of transport stress and summarized a Canadian benchmark study on cattle transportation.
Schwartzkopf-Genswein describes stress as a physiological response to real or perceived stressors. Welfare is affected when animals shift energy away from normal biological functions in response to stress, and the duration and magnitude of the stressor are important in determining the severity of stress.
Transportation involves a number of known stressors, including loading, unloading, an unfamiliar environment and commingling with unfamiliar cattle. Sometimes feed and water are restricted prior to shipping, and environmental conditions such as severe heat or cold contribute to stress. Cattle expend energy maintaining their balance on the trailer, meaning the duration of the trip and the driver's skill level can influence stress.
Researchers today have access to a range of tools for measuring stress. These include blood sampling for analysis of physiological signs of stress such as levels of cortisol or substance P, a neoropeptide biomarker for pain, but Schwartzkopf-Genswein notes the process of obtaining blood samples can complicate results by creating additional stress. Less invasive measurement tools include monitoring behavior such as vocalization, respiratory rate, panting, drooling, feeding, drinking, posture and rumination. Video and electronic monitoring systems such as pedometers and collars that record rumination facilitate behavioral measurements.
Using heart-rate monitors on calves, Schwartzkopf-Genswein says researchers have observed elevated heart rates during the first 30 minutes of transport, which then returned to normal with good driving conditions.
Recognizing a need for benchmark data on cattle transportation, Schwartzkopf-Genswein and her team conducted a large survey of truckers in Canada during 2007 through 2009, asking questions about loading density, distances traveled, use of bedding on trailers, numbers of "downer" cattle, driver experience, travel delays and cattle weight loss. The researchers analyzed data from 6,152 returned surveys covering transport of over 290,000 cattle.
As for transport duration, the data show cattle weight loss increases with longer hauls up to about 30 hours, beyond which the rate of shrink flattens out. Schwartzkopf-Genswein says this does not mean trips longer than 30 hours are acceptable. She believes the slower rate of loss is because the cattle by that time have depleted their moisture reserves, and she recommends a maximum of 20 to 24 hours. Problems with sickness or injuries increase significantly after 25 to 28 hours of travel time.
The survey also revealed a relationship between driver experience and outcomes, with greater driving experience associated with less shrink, fewer lame cattle and lower death loss.
In the Canadian survey, the greatest rate of welfare problems occurred in loads of cull cattle, which is not surprising since these typically are older cattle, often with physical problems that led to them being culled. Calves were intermediate, with finished and feeder cattle experiencing the fewest problems.
Many of the most severe problems occur when transporters use stressful loading methods or load cattle that are unfit for transport. "Even the best transporters and conditions cannot compensate for poor loading decisions," Schwartzkopf-Genswein says.
Bruising remains a concern
Cattle arriving at packing plants with bruises result in economic losses related to beef quality and create animal-welfare concerns, and recent research from Kansas State University shows the prevalence of bruising remains relatively high.
Dan Frese, DVM, outlined results of that research during the recent symposium. Frese is completing his PhD studies at K-State and manages his family's cattle-feeding operation.
Bruises can occur in the feedlot, but transporting cattle to the packing plant can lead to bruising, with horned cattle often suspected of contributing to the incidence of bruises.
To evaluate those relationships, the K-State researchers observed carcasses from 4,287 feedlot cattle at a commercial beef packing plant in southwest Kansas. They recorded whether or not each animal had horns and measured the length of any horns. They evaluated bruising by location and severity, using a "Harvest Audit Program" that divides the carcass into nine anatomical regions.
Among the beef-breed cattle in the study population, only 6 percent had horns, but the bruising prevalence was 51 percent. Among Holsteins in the study, 11 percent had horns and 70 percent had bruises. Of the total number of bruises, 25.6 percent were rated as severe, 35.6 percent were moderate and 38.8 percent were minor.
The study results suggest that horns might not be the major source of bruising in finished cattle, and some other factors during transportation could be involved. Frese says 61.8 percent of the bruises occurred along the dorsal midline, or the backs of the cattle, where horns probably were not the cause. That portion also yields the most valuable cuts of beef, and about one-third of the bruises occurred on the rib and loin areas.
Researchers speculate that overhead clearance for cattle entering the "belly" portion of a trailer could be too low for large-framed cattle, potentially resulting in bruising. During open discussions at the symposium, a representative of a livestock-trucking line said his company has modified its fat-cattle trailers to allow more clearance for large cattle entering the belly section.
The K-State team plans to conduct more bruising research this summer and to look at possible relationships between the location an animal occupies in the trailer and the incidence of bruising.
AABP transportation guidelines
The American Association of Bovine Practitioners (AABP) has developed a set of cattle transportation guidelines, which veterinarians can use in training clients to use safe, efficient and ethical transportation practices.
The document includes general guidelines along with specific recommendations for transportation of calves, stocker and feeder cattle, and culled cattle marketed for slaughter.
The guidelines also include recommendations for transporting cattle that are injured but ambulatory and for handling non-ambulatory cattle. If cattle are unable to be transported and must be euthanized, AABP recommends that veterinarians develop a written plan with their clients for protocols to be used for making euthanasia decisions as supported by AABP and American Veterinary Medical Association, and assist clients with proper training of animal handlers.
The AABP transportation and euthanasia guidelines can be found at aabp.org, under the "resources" tab.
See this article and others on feeding waste milk to dairy calves, the Veterinary Feed Directive rule and the veterinarian's role in protecting consumer confidence in the July-August digital edition of Bovine Veterinarian.