FEDERAL scientists have found that cows are highly susceptible to peer pressure or herd psychology.
The newly reported research involved cows that were taught to avoid eating a poisonous plant. The scientists said the cows did fine when they grazed by themselves. But they started to eat the poisonous tall larkspur when they mingled in a pasture with untrained animals that were enjoying the tasty plant.
''The peer pressure appears to be very, very strong,'' said Michael Ralphs, a scientist at the Federal Agricultural Research Service's Poisonous Plant Research Laboratory in Logan, Utah.
The research was directed toward finding ways to stop the animals from eating the plants. The tall larkspur may kill more than 2,000 cows a year on high-altitude summer pastures in Colorado, Idaho, Montana, Nevada, Utah and Wyoming, Mr. Ralphs said.
Cattle relish the plant, which resembles the garden delphinium, said John D. Olsen, another author of the study. Ranchers build fences or spray herbicides to fight the problem, but both strategies are expensive, Mr. Ralphs said. But he said he is optimistic that some training will help ranchers deal with larkspur and perhaps with other problem plants, like locoweed.
He spoke last week in a telephone interview before presenting the work at the Third International Symposium on Poisonous Plants, which concluded Saturday in Logan.