Still, nobody expects the land of milk and honey days to last forever. Prices have begun to moderate, as production levels in other countries have risen. The shaky global economy is also cutting into demand. China, which had been aggressively importing milk, has pulled back on its milk consumption as well.
Then there's the U.S. dollar, which has been rallying on expectations that the Federal Reserve will start tightening interest rates. A stronger greenback makes U.S. milk more expensive overseas, and the dollar's current levels – it hit an eight year high against a basket of major currencies on Friday –may start to price domestic farmers out of foreign markets.
In fact, the effect is already being seen in exports, which have begun to fall. According to USDEC data, milk exports slipped in the third quarter, and the organization projects a larger impact in the final three months of the year. Export volumes are expected to drop 15 to 20 percent versus a year ago.
With roughly 15 percent of U.S. milk products shipped abroad, the constant supply—cows always need to be milked –weighs on prices domestically. Since liquid milk consumption has been falling in the U.S. for decades, opportunities for growth have come mainly from international markets.
"We're anticipating for 2015 that [price] to average out to about $16.50 per hundred pound," says Brian Gould, professor of agriculture and applied economics at the University of Wisconsin Madison. "That's a pretty significant drop, but $16.50 per hundred pounds is historically a reasonable…price, given what current grade markets are."
Read MoreBlame the cows: Kiwi dollar may stumble
Still, that's a steep drop from the recent $24 per hundredweight (or hundred pounds) peak, which represents a 30-percent-plus drop in price. It's setting off alarm bells for many farmers and futures traders as 2015 closes in. January milk futures trading on the Chicago Mercantile Exchange (CME) are already probing that $16 per hundredweight level.
The slide, and that fact that milk is a highly volatile market in general, is motivating farmers to develop additional revenue streams. The better-than-average profit of 2014 are helping to fund those ventures as well.
The cows at Mystic Valley Farm are becoming the source of another kind of export. Breunig is developing cow embryos from his best Holstein stock to be sold and shipped to China.
"It's allowing us to have another form of income and not have to milk more cows," the farmer said. "Diversification is a really good thing and it helps us weather when milk prices go lower."