Purdue's new USDA Farm Animal Behavior and Well-Being Laboratory, opened this summer, takes a multidisciplinary approach to animal welfare issues.
The new facility, which primarily houses laboratory equipment, covers 2,300 sq. ft. and is adjacent to a 10,000-sq.-ft. laboratory built in 1997. The additional space will allow five scientists in immunology, neuroscience, stress physiology and animal behavior and well-being to investigate swine, dairy cattle and poultry welfare from the animal's point of view.
“Currently, the facility is set to hold 16, 200-lb. pigs in 6 x 6 ft. pens, but we could hold more, smaller pigs in the same pens or we could put in farrowing crates, sow stalls, etc., and make many configurations,” explains Donald Lay, physiologist and research leader for the lab.
The work is aimed at improving current management practices, increasing productivity on the farm, and assisting producers in meeting current and future regulations.
“We're trying to tackle the hard questions related to feelings — pain, frustration and motivation,” says Lay. “These are things that you can't measure, but you can get data that is indicative of various states. The idea is to find out how the animal feels about a situation rather than how we feel about it.
“We want to get away from the idea that humans subjectively decide whether their welfare is okay, and let the animal provide data on these subjective states to allow us to objectively make these decisions,” he adds.
Measuring Fear, Anxiety
Scientists will study swine cognition, fear and anxiety, measuring the levels of the stress hormone, cortisol, in the blood. They'll also study the hippocampus, the part of the brain related to short-term memory and emotional experiences.
Pigs' intelligence and their ability to formulate goals will impact animal welfare. For example, if a sow desires to wallow in the mud, but she can't, she may become frustrated, explains Lay.
Or, if a pig understands that restraint is only temporary, it may feel less stress and be less likely to fight the restraint than if it does not have the cognitive ability to predict its freedom.
Lay and his colleagues will also attempt to determine whether sows being fed adequately, or underfed, is a welfare issue. In a production setting, sows often exhibit the stereotypical behaviors of tongue rolling, bar biting and excessive rooting. Some suggest these activities indicate that their environment is somehow inadequate.
Researchers have hypothesized that this behavior is related to diet and hunger, since they occur most frequently around feeding time, Lay says. One theory is that these behaviors create more saliva, which buffets excessive stomach acid.
“The issue is, you can be hungry, but it's not a big deal,” Lay says. “Or you can be starving to death, which is a welfare problem. But before you change the management of the diet, such as adding roughage, you need to determine where the animal is on the hunger scale.”
Purdue researchers will measure hunger from a physiological and a behavioral perspective. Lay measures the levels of neuropeptides, the hormones related to hunger, at different intervals. Elevated levels indicate the animal is motivated to look for food.
Satiety, or the state of being fed to fullness, can also be measured with the use of diet pills. The hungrier the animal is, the more diet suppressants are needed for satiety.
Mike Toscano, a PhD candidate, designed a feeder system that requires pigs to push up on a bar, in a rooting motion, to open a door that provides access to food. Once scientists train the 5-month-old pigs to perform the test, they can measure the amount of force the pigs use in accessing food, an indication of how hard they are willing to work for their meal.
Data collected from the study can be used to quantify hunger when food is provided at intervals of up to 36 hours, a common interval feeding regimen.
Studying Controversial Issues
This fall, researchers will study pig transportation and processing, and other topics that may elicit public concerns. Lay believes the U.S. reaction to animal welfare issues will soon mirror those in Europe, where industry standards of livestock management practices have been widely implemented.
“Our group is looking at issues that might be contentious for the public, and ones that producers are struggling with,” he says. “We're trying to come up with solutions before they become a problem. So we're looking at sow housing and tail docking — all those issues that could explode tomorrow.”
The highly controversial sow housing issue will continue to be debated, Lay says. The use of farrowing crates can be justified because they are used for a limited amount of time and they save the lives of pigs. They also provide producers with an economic incentive. Gestation stalls are more difficult to justify to those who are unfamiliar with commercial management practices, he adds.
“Most of the people in the U.S. have no clue how animals are raised, nor where their food comes from,” Lay says. “And when they find out, they are immediately shocked. They want the pigs to be free, but they don't know the implications of that either.”
What the critics don't understand, he explains, is that some sows housed in groups will not perform well. Many will suffer from injuries due to fighting over available space, food and water. And some will have less access to these resources than if they were housed in individual stalls.
In a recent Agriculture Research Service/Purdue collaborative study, researchers removed the back section of the stalls, allowing sows to congregate in an alley. As they studied these sows, researchers found they had more lesions from moving between the stalls and the group area. Interestingly, sow performance did not differ between those sows and their contemporaries housed in closed stalls. Growth rates and coping abilities were higher in pigs from group-housed sows, however.
Tracking Salmonella in Pigs
In addition to the welfare studies, the Purdue scientists are studying salmonella infection in swine to understand how infections increase from 5% in market hogs on the farm to as much as 40% at the slaughtering plant, all in a matter of hours.
Donald Lay at Purdue and Scott Willard, associate professor at Mississippi State University, engineered a strain of salmonella that exhibits the luciferase gene, the gene that emits light in fireflies.
Lay will use the new Purdue facilities to study the movement of salmonella in live piglets. A photon imaging camera will show where bacteria congregate in the body and how swiftly it moves through the animal's digestive system.
Until now, this type of research required killing the animal and looking for signs of salmonella infection in the lymph nodes, tonsils and digestive system.
This new research allows scientists to view the engineered bacteria through a sedated pig at various intervals. The next step will be to refine the process for market weight hogs, possibly using fiber-optic probes to follow the routes of transmission.