But Trump's promise has sparked fear and frustration among farmers around the country, who, like it or not, depend on immigrant labor.
"I'm angry," says dairy farmer Mike McMahon, who owns 700 cows in upstate New York, which is now the third-largest dairy producing state and the biggest producer of greek yogurt in the country.
"For someone like Trump or Cruz to say they are going to send them all back is short-sighted because so much of our food supply is dependent on their labor," he said.
Trump's campaign declined to comment for this article and Cruz's did not respond to a request for comment. Neither has not laid out a specific proposal for farm labor.
"It's so easy to blame these Hispanic workers for taking their jobs," said McMahon, a Republican who admits to hiring workers with questionable documentation. But he added, "I can tell you they're not taking jobs. They are filling holes. We need these people. I cannot get local workers to do the jobs that that these guys are doing. And every other dairy farmer will say the same thing."
In fact, half of all workers on U.S. dairy farm workers are immigrants.
Losing those workers would nearly double the cost of milk and cost the US economy more that $32 billion, according to a report commissioned by the National Milk Producers Federation
, an industry group.
Farmers say it's a struggle to find non-immigrant labor to do the work, because the hours are long. It's a smelly, messy job.
"I'm not saying people don't want to work, it's work people don't normally want to do," said Charles Luchsinger, who owns a smaller dairy farm in the same region.
Cows have to be milked twice a day, 365 days a year and Luchsinger said,
"If we don't have labor here to milk, it puts us in a real tough spot."
"We've got committed farmers, intergenerational famers who want to be here, love what they do," said Congressman Richard Hanna, a Republican who represents upstate New York. "They don't deserve to be turned into criminals because they need help to get their work done."
Luchsinger, also a Republican, is a third-generation farmer whose family has owned their land for more than 100 years. He said he doesn't think politicians have an understanding of the work he does. "I don't think that many of the candidates know what it's like to milk cows every day. That's for sure."
He added, "I think if there are people from other countries that are qualified to do the work and are able to work hard, then I don't see what a problem it is having them here to do the work."
Dairy farmers do not qualify for the H-2A program
that allows immigrants to come to the U.S. legally for seasonal work. Dairies need year-round help.
"Cows don't understand shutting off three months out of the year," said McMahon.
"What we need is immigration reform," added Hanna, who wants to re-introduce a Farm Bill to allow dairy farmers to have access to full-time help for up to three years with the ability to renew after that.
"What they need is long-term year round workers that can become familiar with the herds, can manager the herds and live on site with their families," says Hanna.
McMahon defends his actions, saying, "I can't hire anybody who doesn't have documents. Are they real? That's not up for me to decide," he said. "You have no legal way, no real way to track them, but if you had legal access which they would be more than happy to pay to come into this country, then you can track them. C'mon let's fix it."
The National Milk Producers report also found that one-third of all U.S. dairy farms employ foreign-born workers and produce nearly 80 % of the nation's milk.
A complete loss of immigrant labor could cause the loss of one-in-six dairy farms with some 77,000 lost jobs.
"You take the Hispanic workforce away from agriculture, the price of food will go sky-high and you'll be looking at empty shelves," said McMahon. "Good luck at the ice cream stand."