Livestock Haulers Gain from NASA Space Technology

The great cattle drives of the American West are behind us today. Nevertheless, every day several hundred thousand pounds of cattle, swine, and sheep are herded into loading shoots and into livestock haulers for trips to other ranches, or the journey to feeder lots.

These journeys can take several days and cover hundreds of miles. Just like the cattle drives from the old West, it's still hard work and a dirty job. Many of the haulers that run these loads still have to work the livestock to ensure they arrive in good condition and on time.

The trailer manufacturers that build for this industry may have some new changes coming to the design of their trailers. Two factors, fuel cost and livestock health, will drive these changes.

Meat Quality Although fuel costs have been leveling off, higher fuel cost for the haulers may be around the corner. Additionally, political action groups are on the horizon preparing to focus on how livestock is handled during shipping.

According to studies conducted under the guidance of the National Aeronautics and Space Administration (NASA) at the Ames Research Center, evidence shows that new designs might be capable of both improving the fuel efficiency and environmental factors affecting livestock haulers.

An Investigation of the Internal and External Aerodynamics of Cattle Trucks by Dr Vincent U Muirhead, an agricultural professor at The University of Kansas, Center for Research at Lawrence, Kansas, states that environmental conditions that exist during the transit of livestock greatly affect the shrinkage of the animals' weight.

Shrinkage isn't the only symptom that is caused by transit stress. According to Muirhead, the effect of long-term pre-slaughter stress depletes muscle glycogen. This results in darker, dryer meat in both cattle and swine.

Muirhead cites several specific reasons for shrinkage and meat quality corruption: * Air temperature in livestock trailer. * Air movement within the livestock trailer. * Humidity in the livestock trailer. * Wind chill in the livestock trailer. * Distance and time in transit. * Exposure to dust, smoke, snow, rain, hail, and wind. * Degree of excitement in transit. * Space per animal. * Initial body weight and species of animal.

Dying to Get There The trip is particularly stressful for cattle. Dr JA Hoffman's and Dr DR Sandlin's research project for NASA, A Preliminary Investigation of the Drag and Ventilation Characteristics of Livestock Haulers, states that the environment faced by cattle during shipping is a major cause of Bovine Respiratory Disease, also known as shipping fever. In their study, they stipulate that in excess of 5% of the cattle shipped to feeder lots die before or shortly after arrival from shipping fever.

In addition, having the ability to keep the cattle moving through the entire journey is beneficial. This could be done in a more humane fashion by keeping the interior of the trailer regulated with regular airflow for all of the animals.

According to Dr T Grandin of the Colorado State University, in an article prepared for the Journal of Animal Science (1997, volume 75: 249-257), "Cattle feeders have learned from practical experience that 300- to 400-lb calves shipped from the Southeast to Texas will have fewer health problems if they are transported non-stop for the entire 32-hour trip." The article states that the key to performing continuous journeys is building in livestock-friendly climate monitoring and control systems.

Uncovering the Problem The studies carried out under NASA's direction indicate that linking the overall aerodynamic design of the livestock hauler, with an emphasis in improving the interior environmental conditions, would produce more efficiencies in the livestock hauling industry.

"We've pretty much done this the same way for many years," says Muirhead. "Part of that is because it just appears that if holes and slats are used for cattle trailers, enough air should circulate to cool and remove ammonia fumes from the trailer. What we found out by looking at the data is actually the opposite."

Today's cattle haulers are designed with slat or multi-hole aluminum panels that appear to let air into the front of the trailer and exhaust air at the rear of the trailer. But, according to the wind tunnel test conducted at NASA's Dryden Flight Research Center, in many cases air becomes trapped inside the trailers, causing the livestock to breathe the same air many times over for extended periods.

"Air becomes trapped in corners and between shear vortices," says Edwin Saltzman, a researcher for NASA's Dryden Flight Research Center. "Sometimes it appears as though there isn't any air getting into the front of the trailer. Even with frontal openings, there isn't any air getting to the lower two-thirds of the front part of the trailer."

Full size trailer testing was done in Phoenix, Arizona, resulting in the same conclusions. "Dead air space causes several conditions, including ammonia buildup or air depletion," says Saltzman.

Saltzman says that when airflow patterns are analyzed using a trailer combination that would normally be running on today's roads, it's noticeable that the vortices and turbulences are greatly different from what we would expect from casual observation.

"Tests have shown that openings along the forward portion of the hauler's sides are ineffective as air inlets. Most of the air enters the haulers one-third to one-half the distance from the front of the cargo compartment," says Saltzman. "The result is stagnation of air with random flow inside the trailer." Random airflow can be responsible for unfavorable wind-chill factors inside the trailer. This can greatly affect livestock during transportation in the colder climates.

Aerodynamic Trailers Controlling the interior of the livestock trailer can be advantageous to the hauler. Adding devices to the trailer to improve the internal airflow can improve the aerodynamics of the tractor-trailer combination.

When the first part of the study was commissioned, an important part of NASA's Energy Efficient Livestock Hauler (EELH) was the cab-over-engine (COE) tractor used for the power source. Today, the COE design has lost favor with many of the haulers involved in the transport of livestock.

A conventional tractor, especially utilizing the aerodynamic designs that have evolved since the early 80s, can achieve results that mirror the COE design, according to a 1997 Department of Transportation study conducted in Phoenix, Arizona.

However, even without utilizing the COE tractor design, livestock trailers that are manufactured aerodynamically efficient with an ergonomic design will benefit the livestock.

Air and Climate Control The cornerstone to a newer design is the submerged inlet. The submerged inlet was developed early in the 1940s to provide a way for aircraft to ingest air at both low and high speeds. The submerged inlet actually pulls air into the half-funnel system, instead of having air rammed into the front of the device. "The device is very successful when mounted in-line with the air flow that you're trying to attract," says Saltzman.

The study emphasizes that careful incorporations of the submerged inlets on livestock trailers can provide ventilation and reduce drag coefficients. The amount of air captured can be monitored and regulated by either manual or thermostatic means.

According to an artist's renderings provided in several NASA reports, future trailers might combine a system of frontal fairings for directing air, submerged inlets, and round exhausting vents for the rear of the trailer.

Some swine haulers are demanding more precise climate control measures. "In some applications, it makes sense to have a fully regulated and refreshed air supply coming into the trailer," says Saltzman. "That requires air-conditioning or, in some cases, the addition of a significant heater be installed in the trailer."

Full air-conditioning with both heating and cooling capabilities aren't that far out of touch judging by the request made on the M H Eby Company. "Air flow management is not new to the livestock hauling industry. Several options are available to add or block external air flow when necessary. Based on customer feedback, they are reasonably effective," says Travis Eby, manager of sales and marketing for the Eby company. "Shippers and growers want to improve the overall conditions, especially for swine weanlings, and they want them to arrive in pristine condition. Climate controls are helping to enhance that situation."

"There will be some significant changes in livestock trailers in the not-too-distant future," says Saltzman. "The technology is there. Now it's just a matter of economic pressure being applied to make it cost effective for the industry to change its style."

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