COCHRANE, Wis. — Dozens of calves groaned as Hermenegildo, a young Mexican farmworker, wheeled out a cart with bottles of milk. He attached the bottles to the wood pen of each calf, walking up and down the row as the animals guzzled the milk in minutes. The 600 cows on the dairy farm produce 5,000 gallons a day, which are trucked for processing into cheese at a plant owned by a Minnesota cooperative.

Farm owner John Rosenow credits immigrant labor with sustaining his business, estimating that at least 90% of the workers on Wisconsin dairy farms are unauthorized. He turned to Mexican migrants 25 years ago, he said, when he could no longer find American citizens to do the work.

Now, Rosenow believes that if GOP presidential nominee Donald Trump fulfills his campaign promise to carry out mass deportations, it would devastate the $45 billion dairy industry in America's second-largest milk producing state.

"It would basically destroy it," said Rosenow. "There would be shortages, there would be very high prices, and that would last for quite a long time."

Yet, in campaign stops in this crucial battleground state, Trump has promised to end what he terms a "mass migrant invasion" of Wisconsin. "They come in illegally, they take everybody's jobs, and you don't know who you're hiring," he said. "Our country is being destroyed." Pro-Trump signs cluster the roads near Rosenow's farm.

Rosenow, a Democrat, said local farmers who support Trump think the candidate doesn't mean what he says about mass deportations. There was a lot of fear in the immigrant community when Trump was president and most farmers Rosenow knew lost a few employees, who fled the country. But after about six months, they started coming back.

"It's just like a lot of things in politics," Rosenow said. 'Rhetoric is one thing and reality is another."

Immigration is one of the largest issues shaping the campaign between Trump and Democratic nominee Kamala Harris. Both are promising tighter controls at the country's southern border, but Trump has vowed to undertake an unprecedented effort to deploy the National Guard to send back millions of unlawfully present immigrants.

"I think when you talk about the mass deportation of any group of people, you're going to see a ripple effect throughout the entire economy — agriculture would feel the effects as well as any number of other industries in the country," said Tyler Wenzlaff, director of national affairs for the Wisconsin Farm Bureau Federation.

Dairy farms may be among the hardest hit if mass deportations happen.

The work, which is usually in rural areas that have been losing population, is grueling and requires long hours. The National Milk Producers Federation says dairy farmers find it challenging to recruit and keep native-born employees, and immigrants account for half of all workers.

Last year, the University of Wisconsin estimated that more than 10,000 unauthorized workers are employed on Wisconsin dairy farms. In Minnesota, where an estimated 81,000 immigrants without legal status live, the state dairy industry's reliance on such labor came to light when Attorney General Keith Ellison sued owners of a Stearns County dairy farm for withholding at least $3 million in unpaid earnings from unauthorized immigrant employees.

George Braunreiter, a retiree in nearby Alma, Wis., and a Trump supporter, said he's "all for [immigration] as long as it's legal, and if it isn't they need to suffer the consequences. We have laws and rules and people should obey them. You can't have lawlessness."

He said illegal immigration hurts everyone because immigrants are willing to work for less than those who are here lawfully.

Matt Bocklund, a Hudson, Wis., Republican activist said in a statement that the Biden administration's border policies, along with the State Department's refugee resettlement efforts, could lead to exploitation in the farming industry, where many refugees and immigrants are vulnerable because of weak labor protections and their legal status. That strains rural communities, many of which are already facing economic burdens, he said.

He suggests creating incentives for farmers to use only legal labor; offering tax incentives, job training and possibly wage subsidies to encourage American workers to fill jobs now held by immigrants; and penalizing farmers who hire unauthorized workers while encouraging investment in automation through tax credits and subsidies.

In 2020, 62% of Buffalo County, home to Rosenow's farm, went for Trump. And Wisconsin's largest milk-producing counties also backed the GOP nominee by hefty margins. Trump lost the past two elections in Minnesota, but in Stearns County, the state's largest milk producer, 60% of voters backed him.

Out of necessity

In the late 1990s, Rosenow recalled, it was a struggle to find workers: "The only people that would even respond to an ad were people that had major problems — work histories and stuff where they had dependency issues or they weren't reliable. … Most Americans won't work on farms."

"We were desperate for help," he said. "We turned to immigrants. And we didn't want to do that; we didn't know the language, and we didn't know the culture … but once we did, we found out how wonderful they were, great workers, great people to be around and people you want to have as your neighbors."

Today, 13 out of his 18 employees are Mexican. He fills out I-9 and W-4 documents for the workers and said they pay state and federal taxes "like everybody else." Federal legislative efforts have repeatedly failed to allow dairy farm workers into the legal agricultural guest worker program under the H-2A visa.

A workforce shortage is the top issue that Wenzlaff hears about from dairy farmers, and a committee at the Wisconsin Farm Bureau is examining the issue and meeting with state and agricultural leaders about it. He supports expanding the H-2A program to include dairy workers and making it more efficient.

"We can still have a secure border while also providing a stable workforce, and the expansion of guest worker programs or visa work programs can help mitigate some of the agricultural workforce issues that we're seeing," added Wenzlaff.

He said the majority of dairy farmers who are members of the federation probably lean toward Trump, and Wenzlaff hasn't heard anything from them regarding the mass deportation plan. The Wisconsin Farm Bureau Federation usually backs Republicans for Congress, though it doesn't endorse presidential candidates.

Hermenegildo's father has been working on Rosenow's farm for nearly a decade. His son joined him two years ago. Hermenegildo sends most of his earnings home to their family in Mexico and wants to eventually use the money he makes at the dairy farm to build a house there. The workers live in free housing on the farm, occasionally buying groceries in Winona and going to a shop in Arcadia to send money back to Mexico. Most make about $40,000 a year.

Hermenegildo said the workers have talked about Trump's immigration plans and "are afraid of being deported. They wouldn't want to go back home … what they're doing here supports their whole family."

As he tended to the calves, another young Mexican migrant wearing rubber boots guided cows into the milk parlor for their thrice-daily milking. The worker disinfected the animals' teats and attached units to the udders through which milk flowed; it traveled through a stainless-steel pipe, was pumped into a cooling system and sent into a tank. Then he ushered the milked cows back to the barn and brought in another batch for milking. At a nearby barn, other Mexican men attached a plastic tarp to the exterior wall to keep the cows warm.

"They work really fast," Rosenow said of his employees. "We don't tell them to work really fast; they want to work really fast."

Ramón, another dairy worker, left his partner and their two children in Mexico to come to Wisconsin. It was difficult, he said, "but you're leaving for the well-being of them so you can get your family ahead." Here, he moves manure, patches barn roofs and does other jobs around the farm.

Ramón has heard Trump's rhetoric about mass deportations but doesn't understand it.

"I just don't know why they don't let us work here," he said. "All we came to do is work."