Transport to Slaughter: Searching for a Good Ride

The overall goal of research being conducted by Texas A&M University's Ted Friend, DVM, is to develop a scientific basis for making reasonable guidelines for transporting groups of horses on long trips in tractor-trailers. In other words, what is the best, least traumatic, safest way of transporting horses to slaughter.


Courtesy Texas A & M University

Some horses get their heads down in the trailer and cannot get them up.

Friend, who is a professor of applied ethology (biological aspects of behavior) with the Department of Animal Science, through the years has overseen a wide range of projects studying stress- and welfare-related issues, including transportation of horses and cattle. In the past, much of the transportation of horses dealt with smaller trailers and how travel affected athletic performance or breeding. This is the first research dedicated to the quest for answers in how best to transport horses to slaughter.

There are a series of studies being undertaken by Friend and his colleagues. While the statistical analysis is still underway, there are some preliminary observations that could point to what will become scientific fact.

One study looked at orientation, or how horses prefer to stand, when being transported in tractor-trailers. Friend said that from observations recorded in the studies, horses preferred to face at a 45° angle. He observed that when given enough room, most horses aligned themselves in this manner. He said it didn't seem to matter whether the horses faced forward or backward in the trailer, they still would try to stand at a 45° angle.

Other research looked at how difficult it was for horses to maintain their balance and how much they slipped during transportation in these trailers, and another project tried to define fatigue and dehydration based on travel time.

For some of these studies, specially equipped, open-topped trailers were used. The open tops allowed for thermal heating (not difficult in a Texas summer), as well as set-up of over-head video cameras to record movement, slippage, positioning, and behavior.

In research on dehydration and fatigue, 20 horses were divided into groups of five in a large, single flat-decked trailer and placed in four pens in the trailer. Two of the groups were given water periodically when the trailer was stopped for vet checks and to draw blood for laboratory testing. There also were control horses in a large, round pen in full sun. Half of the controls received water at the same intervals as the shipped horses, and the other half did not.

"Usually it takes 24 hours (of travel) before we start seeing dehydration," said Friend.

He said earlier research has shown that very few horses have problems with dehydration in the first 20 hours of transportation. Friend said he expected to see lab results in this study that reflect research conducted two years ago. That research showed that after six hours of being removed from water and then transported for 24 hours, there were elevated electrolyte levels and serum proteins, and some horses were starting to run a fever. A fever could indicate that some were dehydrated to the point that sweating was becoming impaired. It was not severe dehydration at that point, but horses were fatigued and were holding their heads down.

"Horses can go a fair amount of time without water, but we also have to develop guidelines regarding how you put them back on water without causing colic and other problems," he noted.

The earlier research also reflected that a few horses were reluctant to drink water during stops while still on the trailer until after 24 hours of transport (30 hours without water).

There are water systems that have been developed for tractor-trailers that could allow horses to be watered during stops. These collapsible troughs can be filled with a hose. The water remains in the troughs during the duration of the stop, and the horses can drink until they are satisfied. Then the troughs are drained and collapsed before another leg of a trip commences.

"Some people's experience is that you have to stop for a certain amount of time before horses will drink," said Friend. "Most countries are using the logic that if you provide water on-board, you can extend travel time. It could be a reasonable compromise. If you have to haul horses more than 24 hours, then the truck must be equipped with a watering device. But you still need to set an upper limit (of travel time) that horses can't exceed."

Because the trailer with the video camera exceeded most height requirements for getting under bridges and electric wires, an alternate site was found to conduct research on orientation and density that required video monitoring. The Texas Transportation Institute Proving Grounds is a former World War II bomber base where various testing is undertaken (crashing cars, various research on planes, etc.). A course was set up that had specific turns, bumps, and distances.

Orientation studies not only looked at the preferred angle for standing, but how horses shifted to compensate for various turns (including 120- and 90-degree turns), bumps, and road conditions.

"I don't think the bumps bothered them much except to contribute to fatigue," said Friend.


Some of the density and orientation studies were done in conventional double-decker trailers. Current thought in the transportation industry is that it is more efficient and profitable to pack in horses so they "hold each other up." That was found to be false in initial observations.

The clearance in the typical double-decker, or possum-belly, trailer is 5 feet 10 inches in the lower belly. However, deduct about three or four inches from that height for the support beams that traverse the space at about 1 1/2-foot intervals. The upper deck does not have the support beams, and is about two inches higher.

There are two other "pens" in a typical double-decker trailer, one in the front and one in the rear. Those pens usually have very high ceilings. Friend found that if the university's research horses were loaded from the back or front of the trailer (as is the case in most hauling situations), that many of the horses couldn't get up and down the ramps without banging their withers, even if they were the smallest horses in the group.

"The taller horses were really a problem," he noted.

At the suggestion of Erika Berg, one of the graduate students working on the project, head protectors were placed on the horses. While horses going to slaughter will never have that luxury, Friend decided that the university's research horses could be observed just as well with the protectors in place and that it wouldn't bias the study.

In the lower belly, Friend found that some horses could not get their heads up, and some that did found their heads caught between one of the support beams and the rump of another horse. (Horses were loaded head-to-tail to maximize load and mimic typical hauling conditions.)

"Some horses could raise their heads and rest them on the rump of another horse," said Friend of animals in the lower belly. "The horses banged their heads several times (on the beams) before they learned how to manipulate in that space."

"Our initial observations show that density will be a problem," said Friend. "But if you decrease the density, you increase the cost per horse to haul them."

There were increased numbers of injuries, abrasions, kicks, and horses stepping on each other as density increased, he noted.

"But I think if they have enough space, they don't need support. With four legs, low density, and good footing, they are very stable even in high-G turns. With lower density, they can brace and follow (the movement of the truck) and maintain their balance, and manipulate to get out of each other's way. They can raise or lower their heads. When they are crowded, it is more strenuous because they are constantly interfering with each other's balance and aggressive horses can be a real problem, moving and biting."

He said aggression increases dramatically when horses are crowded on the trailers.

"If one wants to get its head up and can't, or vice versa, they bite their neighbor trying to get them to move and give them room. The problem is that the neighbor can't move, so the horse just keeps biting and biting.

"Aggression in this case is not caused by fighting for dominance, but of wanting another horse to move."

Future Studies

Studies that still need to be done, according to Friend, involve horses actually purchased from auctions rather than research horses from the university.

"Tame horses will drink, but will the horses from the auctions?" queried Friend.

Using auction horses will have its drawbacks, however, because they will be much more difficult to handle, inspect, and take blood samples.

Funding for the initial studies came from USDA competitive grants of the National Research Initiative. These highly competitive grants are designed for agricultural research. The current grant used for this transportation study was ranked fourth out of 164 submitted. The USDA can fund only about 20% of the requests it receives for these peer-reviewed grants, so it isn't necessarily a reliable source of continuing funding. More money will have to be found to continue research that could lead to guidelines for humane and safe transportation of horses to slaughter in commercial trucks.

About the Author

Kimberly S. Brown

Kimberly S. Brown was the Publisher/Editor of The Horse: Your Guide To Equine Health Care from June 2008 to March 2010, and she served in various positions at Blood-Horse Publications since 1980.

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