In January its members campaigned against and helped defeat the LDP's candidate for governor of Saga, a prefecture in farm-heavy southwestern Japan.
Though agriculture is only about 1 percent of Japan's economy, that defeat worries those who fear the government could temper what Koichi Kurose, chief economist at Resona Bank, calls "a symbolic part of Abe's structural reforms" ahead of nationwide local elections in April.
"If they pull back from that to win elections, they can pull back from the whole Abenomics reforms," he said.
"Foreign investors are also watching closely whether or not Abe can carry out agricultural reforms, which will affect their evaluations of Abenomics," said Chizu Hori, senior research officer at Mizuho Research Institute Ltd.
At home, farmers hurt by another plank of Abenomics - loose money and a weaker yen - are also watching closely.
Hiroyasu Sugiura, 67, whose dairy lies in the shadow of Toyota Motor factories in central Japan, says he is desperate.
The tumbling yen helps exporters like Toyota but has led to a sharp rise in feed costs, which now swallow nearly 80 percent of Sugiura's dairy revenue.
Read MoreAbenomics gets a mixed report card
"The weaker yen ... may have given Toyota Motor trillions of yen in profit, but we are getting squeezed by the same national policy," said Sugiura, who is also the head of the Aichi Dairy Cooperative. "We want the government to protect us."
For the consumer, however, high prices and a recent butter shortage are the pitfalls of a closed market for milk and dairy products, where output volume and sales prices are set by the state and a few designated groups under the JA, while imports are under effective state control.
Raw milk production was 7.45 million tonnes in the year through March 2014, down from 8.66 million in 1997, while the number of dairy farmers has fallen to 18,600 in 2014 from 160,100 in 1975. Cow numbers have fallen by a third from their peak.
Meanwhile, Japan imposes a 360 percent tariff on butter imports to protect domestic farmers while maintaining an import quota as a condition for such high tariffs under international rules of trade.