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U researcher Yuzhi Li

Scientist Yuzhi Li is experimenting with housing systems for sows and piglets at the West Central Research and Outreach Center in Morris.

A life of leisure

U researchers studying better housing for livestock animals

By Becky Beyers

From eNews, July 24, 2008

It seems logical: A contented livestock animal is a productive one. And of course farmers want the best for their animals. But animal comfort issues have to be balanced against the need to make a living. Productivity and economics usually take precedence over providing all the comforts of home in the barn. That choice is becoming less black-and-white in some livestock barns, as consumers seek food products from animals raised under more humane conditions, and as research by scientists at the University of Minnesota's College of Food, Agricultural, and Natural Resource Sciences helps find new ways to keep animals happier without breaking the bank. The following are two examples of what the U is doing for pigs and cows.

Eliminating stalls for swine

Pigs are animals that naturally socialize with each other, says Yuzhi Li, an assistant professor of animal science who works on alternative swine systems at the U's West Central Research and Outreach Center (WCROC) in Morris. But most sows are housed in tight-fitting stalls during pregnancy and farrowing that restrict their movements. The stalls became the industry standard in the mid-1970s because of their efficiency, but researchers have found some sows' behavior and health decline while confined. Li has been testing sow group housing, where sows and piglets move around freely in a pen with thick straw bedding that absorbs most of their manure. The setting allows each sow to choose its micro-environment and companions, resulting in more natural behavior with less risk of lameness and difficult pregnancy and birthing. Gestation stalls have been outlawed in Europe; in the United States, movement away from them has been driven by consumers, rather than legislation. Last year, the nation's biggest pork supplier, Smithfield Foods, says it was responding to demands from its customers--including McDonald's--by requiring its growers to phase out gestation stalls in the next 10 years. Those changes eventually will filter down to Minnesota pork producers, Li says. While fewer than 5 percent of producers now use group housing of both gestating and farrowing sows, she expects that number will grow as scientists find ways to solve the challenges of group housing--primarily sows that crush their piglets by lying down on them and aggression and biting between sows. Gathering more data will help find solutions to those problems, Li says. For example, two studies at the WCROC may help reduce the sows' aggressive behavior and reduce piglet mortality. One involves adding tryptophan--the same amino acid that is believed to make humans sleepy after Thanksgiving dinner--to the pigs' diets to reduce their aggression. Another behavioral study shows that first-time mothers who crush their piglets tend to do so with subsequent litters; it's possible that eliminating those careless mothers from the herd will eventually help reduce piglet mortality, Li says.

Flies: A never-ending problem

Roger Moon has spent years dealing with a different animal comfort issue, one that has no easy solution: flies. "For horses, it's mainly a question of comfort, but with food animals it could affect their productivity," says the professor in the U's Department of Entomology. Until about the 1940s, flies were simply a fact of life; since the advent of insecticides, animals can get some relief, but the insects have evolved resistance in some cases, and eliminating all flies just doesn't seem possible. Four main kinds of flies affect livestock in Minnesota: the stable fly, the horned fly, the house fly and the face fly. Stable flies in particular can affect dairy production, because in summer heat, the cows bunch together and don't eat as much while trying to get away from the flies. Face flies have a more visible effect--they can cause pinkeye in cattle because they feed on tears and mucus around the cows' eyes and nose--but no one has traced that discomfort to a direct effect on productivity, Moon says. "It's difficult to deal with pests in animals," he says. "For plants, dealing with pests comes to simple economics. But with animals, there's this other dimension." While Moon has researched the question of biological control--finding a natural enemy that could be introduced in Minnesota barns to eliminate flies--the search found few possibilities, he says. "Our basic sermon to farmers at this point is to understand where the flies come from and try to eliminate these sources through prevention, sanitation, and waste disposal, including composting. Source reduction is really about the only thing that works." To learn about the U's research with housing for cows, read Got more milk?" and "Maternity spa for cows" .