When Darin Mann decided his future lay with the family feeding and farming operation in Parma, ID, he and his father Kent knew M/M Feedlot had to expand. One big challenge was how to dispose of the manure produced by an additional 4,000 head. Their resolution wasn’t more land, it was less manure – via composting.

M/M Feedlot lies about an hour west of Boise. The operation got its start back in 1947 when Darin’s grandfather settled in the area, cleared out the ubiquitous sagebrush, leveled the land and installed an irrigation infrastructure. Kent returned to the family operation in 1972 upon graduating from Brigham Young University (BYU). By that time, cattle feeding had been added to the operation.

In 1982, the operation added another component, a dairy heifer-development enterprise, which Kent eventually grew to 6,000 head. Today, the operation has a one-time capacity of 12,500 head and supplies replacement heifers to six large dairy operations in the Northwest.

Those dairy calves come to the M/M Feedlot at six months of age; at 12-13 months of age, they’re bred artificially to their owners’ specifications. At 20 months of age and about seven months pregnant, the heifers are returned to the dairies, where they give birth and enter the milking string. Their calves will return to M/M Feedlot and the cycle continues.

Darin graduated from BYU in 2001, after which he and wife Alison spent a year in China teaching English. He returned to the family farm operation nine years ago.

“Because manure contains a high percentage of water, it was cost-prohibitive to spread it on crop ground more than three miles from our feedlot,” Darin says. “We could only spread manure two times/year – after the fall harvest and before spring planting. That meant we had to stockpile manure for basically six months.”

The Manns began composting on a small scale about seven years ago, trying to learn “the science and the art,” as Darin puts it. “Once we kind of figured out what we were doing and the market, we set aside some land, got some equipment and jumped in big time about four years ago.” Today, they compost almost 100% of the manure produced in their feedlot.

The composting program results in corrals getting cleaned year-round and the concrete pads around the feed bunks and water troughs weekly. Cleaning is done with a tractor and a box scraper, moving the manure into concrete holding areas.

Once the holding area is full, the manure is transported to one of two composting areas on either side of the feedlot. Constructed of packed natural clay, the two composting areas comprise about 30 acres. At the low end of each composting site is a large collection pond to capture runoff. The runoff is used as added moisture to the compost windrows during the first stage of the composting process. 

Once the manure reaches the composting site, it’s placed into a 6-ft.-tall, 16-ft.-wide windrow about 800 ft. in length. Typically, the Manns have a total of 40 windrows under management. Once the windrows are constructed, it takes approximately 120 days for the composting process to be completed, depending on temperatures.