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Archive for the ‘Graduate Student Research’ Category

From Pig Hairs and Genes, A Possible Solution to a Nagging Problem

Even the technological wonders of genetic science can still require some basic, mundane tasks, like cutting pig hairs.

“I spent many, many, many hours snipping the roots of pig hairs,” says Kaitlin Wilson, a Washington State University master’s student in Animal Science. She processed five to seven hairs per pig, in fact, from a total of 272 pigs.

“It was a lot of hair,” says, Wilson, who raised cows and pigs for 4H while growing up on a Connecticut horse farm. “It took me days, hours and hours and hours.”

Pig's tail photo courtesy of http://www.flickr.com/photos/ashleyb/

But inside those roots lay just enough DNA to determine each pig’s genetic makeup. And by comparing their DNA, Wilson and colleagues here and in Norway found what they believe is the first genetic basis for a particularly gruesome and costly problem: tail biting.

Pigs biting each other’s tails are a big problem. It’s painful and leaves the victim prone to infection.

“We’re not just talking a little bit,” says Holly Neibergs, an assistant professor of animal genetics and Wilson’s advisor. “We’re talking about a kind of mutilation here. They make these huge holes, which isn’t good.”

Farmers in the United States get around the problem by docking, or cutting, pigs tails. This in turn has been criticized as a cruel practice, which is why it is restricted by the European Union. Meanwhile, many EU pigs are getting their undocked tails bitten. One study found roughly one in every 12 pigs falling victim. Factored out over the EU’s 152 million pigs, that’s roughly 13 million bit pigs.

The behavior is thought to stem from modern facilities that don’t have earth or hay in which pigs can play, forage and root. Frustrated, they bite and chew tails. The biting is reduced with more space and materials to mess about in, but that doesn’t eliminate the problem.

Thinking the behavior might also have a genetic component, Wilson processed hairs from Norwegian crossbred pigs that were either biters, victims or neither. She found that, yes, biting pigs had several similar stretches of DNA in their genes. Moreover, she found that victims also had stretches of DNA in common. Biting’s heritability—the degree to which the behavior can be passed between generations—is significant enough that selective breeding can help reduce the number of biters and their victims, Wilson says.

“Who knew the things they could do with genetics?” says Wilson. “I can only imagine where this is going to go in the future.”

Wilson presented her findings at the 2010 Dr. William R. Wiley Exposition of Graduate and Professional Studies held last month in the CUB. Her poster can be seen here (pdf).