By SUSAN MONTOYA BRYAN, Associated PressALBUQUERQUE, N.M. (AP) — Miles of fencing separating a national preserve from forested grazing pastures in northern New Mexico have been compromised over the years by wildfire, falling trees and herds of elk.Cattle have found their way through the porous border of Valles Caldera National Preserve, their numbers escalating over the dry summer months to what park managers described as "critical mass" despite attempts by some owners to herd the livestock out on horseback.Park rangers initiated a roundup last week after getting complaints from visitors and anglers, prompting a showdown with ranchers who say cattle were held with little food or water and it's up to the federal government to mend the fences.Chris Lovato said he spent much of the summer gathering cattle that had wandered out of his grazing allotment on the adjacent Santa Fe National Forest in search of grass and water in an area hit hard by drought."It became a revolving door because 80 percent of the fence is down," the 70-year-old rancher said.Each time, he called park rangers and forest managers to let them know he would be riding in on horseback. He also asked whether the fence would be fixed.The answer, he said, was no.In New Mexico, state law puts the burden on landowners to erect fences if they want to keep out trespassing animals. Before Valles Caldera was turned over to the Park Service, the trust that managed the expansive property handled the maintenance, and forest officials say it's generally a shared effort among neighboring property owners.But officials at Valles Caldera say federal courts have upheld the principal that state fence-out laws are generally pre-empted by U.S. regulations requiring livestock owners to keep their animals off certain federal lands."While we will continue to do our part to maintain our boundary fences, there's no obligation for the Park Service to fence out potential trespass livestock under state laws," preserve Superintendent Jorge Silva-Banuelos said. "The adjacent livestock owners do have a role to play in the maintenance of their allotment fences that border the preserve."Rather than issuing citations or fines, preserve officials said they wanted to handle the trespassing cattle informally by rounding them up and calling a state brand inspector to identify the owners so they could be trucked out.Ranchers argue that the preserve should have posted a notice of their intention to impound the animals. They say more than 300 cows, calves and some bulls were corralled without hay and with little water for days until they could make the 300-mile (483-kilometer) roundtrip to trailer the livestock home.One cow died, and ranchers have reported that the animals were in bad shape.Lovato made multiple trips last weekend to move eight loads of cattle after he was told he wouldn't be allowed to herd them by horseback less than 2 miles back to his allotment."The federal government, instead of helping us, they're just punishing us after what we faced this summer," he said, referring to the challenges of the drought.Silva-Banuelos said trespassing livestock have long been a problem at the preserve and federal regulations spell out how it must be handled."It's a pretty routine activity, but as we start getting more and more complaints from visitors and anglers, it's something that we have to make sure that we're upholding our obligations to protect and preserve the resources that Congress established as a national park," he said.Dubbed the "Yellowstone of the Southwest," Valles Calderas is home to vast grasslands, the remnants of one of North America's few super volcanoes and one of New Mexico's most famous elk herds. The bear claw-shaped ring of mountain peaks that form the caldera is culturally significant to neighboring Native American tribes.Gary Ziehe, who was the first executive director of Valles Caldera after the federal government bought it, said the fence has been difficult to maintain since some stretches cross remote and rugged territory.Ranchers hope a solution can be found, and Silva-Banuelos said he plans to meet with some of them."We want to be good neighbors," Ziehe said.