Casey Guernsey, a seventh-generation dairy and beef farmer, told CNBC on Thursday that the U.S. agriculture industry needs trade certainty and he supports President Donald Trump's mission to seek fairer deals.

The timing for a possible new U.S.-Mexico-Canada pact to replace the 1994 North American Free Trade Agreement couldn't come at a better time, said Guernsey, a spokesperson for the Americans for Farmers & Families coalition and a former Missouri state legislator.

"We need to look toward the future with optimism because these last few months, especially, have been a real roller coaster," he said. "Farmers have been dealing with low commodity prices," due to trade uncertainty, and volatile weather, he added.

NAFTA has been such a win for U.S. farmers that "we've kind of taken it for granted and now we've seen what it looks like with a potential of losing those trade agreements," Guernsey admitted. But he's optimistic Canada will resolve its trade differences with the United States and join Monday's deal between the U.S. and Mexico.

Negotiators face a Friday deadline, set by Trump, to get a three-way deal or move forward bilaterally. The administration needs to give Congress 90 days notice of changes to NAFTA.

U.S. officials want Mexico's outgoing President Enrique Pena Nieto to sign any deal before leaving office on Dec. 1. Waiting until Andres Manuel Lopez Obrador takes office could complicate the process since the talks began in January 2017 on Pena's watch.

"Farmers are the ultimate realists," Guernsey said. "[We] know what works. That is these trade deals. That's why we've [as farmers] supported the president as long as we have and when we did, because we needed someone who's going to fight for us."

Since the NAFTA replacement and trade disputes with China remain unsettled, the Trump administration is initially making $6 billion available in emergency aid to farmers, starting right after Labor Day. The Department of Agriculture has authorized up to $12 billion for farmers.

Agriculture Secretary Sonny Perdue told CNBC on Wednesday that the relief won't make farmers "whole," but will help them avoid a disastrous season.

Guernsey said Thursday, however, that farmers would rather have those trade disputes resolved than rely on government relief.

"Those aid packages only make farmers more dependent on the government. We don't want that. We don't want to wait until the end of the month for a paycheck," he said, adding that fair access to sell in markets all around the world will ensure there's an eighth generation of his family in the business of farming.