EUGENE, Ore. - You often see them on the side of the highway: tall bright colored weeds engulfing the hillsides.
But these little weeds are causing big problems for Oregon's livestock.
"A plant like this can kill a horse," said weed expert Carol Mallory-Smith pointing to a tansy ragwort flower. "It can harm animal health if it's poisonous."
According to agriculture experts, many of Oregon's pastures have noxious weeds such as spotten knapweed, bull thistle and the highly toxic tansy ragwort. Experts say some plants can cause choking and even death if consumed by livestock like horses and cows.
"We receive reports of about 100 animals each year," said weed expert Andy Hulting. "So we know it's a continuing problem."
The invasive plants can degrade pasture quality and can push out vegetation for livestock. When that happens, the animals resort to eating something they usually wouldn't eat - poisonous weeds. Eating these plants can result in death.
"Sometimes the symptoms can be immediate and other times it may be weeks to months," said Hulting.
The United States spends about $138 billion dollars a year to get rid of invasive plants.
Here in Oregon, we dedicate about $48 million each year to eradicate these weed species.