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Pig Composting

The affordable technology can solve a difficult problem.When it comes to dead farm animal disposal, the problems have been piling up. Farmers are finding it harder and harder to properly and legally get rid of dead animal carcasses.One effort to change all that is a program started about a year ago by the Minnesota Board of Animal Health. The board permits composting of poultry, swine, sheep and goats.In

The affordable technology can solve a difficult problem.

When it comes to dead farm animal disposal, the problems have been piling up. Farmers are finding it harder and harder to properly and legally get rid of dead animal carcasses.

One effort to change all that is a program started about a year ago by the Minnesota Board of Animal Health. The board permits composting of poultry, swine, sheep and goats.

In the last year, the board has assisted about a dozen pork producers in setting up the first, officially recognized composting facilities in Minnesota. Officials are promoting the concept as an environmentally sound means of disposal. No permit is required.

Situation Becoming Urgent Composting is a system for the times in Minnesota, because the average pork producer is about out of options, points out Carl Denkinger, law compliance representative with the state board of animal health.

For example, a 1,000-sow operation loses 20 tons of dead animal material every year, and the options for disposal are dwindling, he observes.

Renderers almost refuse to pick up a bunch of dead hogs when they can get a much higher return from a few cattle carcasses, he explains.

The problem there, though, is the Food and Drug Administration has imposed a total ban on ruminant-to-ruminant feeding due to BSE (Bovine Spongiform Enteropathy). It has crimped business, reducing the total number of renderers that serve both cattle and hog producers. Service is spotty, explains Denkinger.

Biosecurity concerns about rendering trucks driving onto farms has led a number of hog producers to develop an off-site removal system, he says. A covered, containment facility improves biosecurity, but there is a 72-hour time limit for rendering companies to pick up the deads. Here again, poor rendering service has reduced the viability of this option for producers, says Denkinger.

Burial is somewhat effective, but Minnesota regulations require carcasses to be buried 3 ft. deep, he says. In some locations, the water table is too high to bury that deep.

Plus, Denkinger says, not many producers have the proper equipment to do a good job of burial.

He observes: "The common method of disposal by larger pork producers was to dig a pit in the fall, throw the pigs in and cover it over when it was filled, then go on to another one. Unfortunately, five to six years later, when you dig in, those carcasses are still there waiting for you. They don't decompose very well."

Denkinger says producers have good intentions. They pile up some dead pigs, intending to dispose of them later. Come spring, the pile is still there.

Composting Solution Pig composting can be done in a new or existing, covered, open-front facility.

To start a compost, apply a 1-ft.-thick layer of bedding as a base, followed by a foot-thick layer of deads and a 1-ft.-thick layer of bedding as a cover. If guidelines are adhered to, composting is simple. "It's not rocket science, but there are some basic principles that you need to follow," says Denkinger. (See Table 1.) Adding manure is optional but speeds up the composting process.

Composting Recommendations Denkinger has developed these composting recommendations:

* Maintain the proper carbon (bedding) to protein (deads) ratio. It should be 2:1 based on volume. (See Table 2.)

* Keep the proper moisture level. "People are afraid of getting it too wet. It should be almost to the point where you can wring water out of it, where it will clump together." (See Table 3.)

* Follow proper carcass disposal. "You can have all the carbon source in the world and proper moisture, but if the carcasses are all piled on top or are laying on the cement, it's not going to work. They have to be distributed in a layering process, a minimum of a foot away from the floor and the walls to allow composting to work evenly."

In order to add a large sow or boar to the pile, a trough can be dug into the existing layers to accommodate the carcass.

* Use a good carbon source. Shredded, chopped corn stalks will work, the finer material the better. That's why sawdust works so well, says Denkinger. Turkey litter is another popular source because of availability in the state.

* Allow for proper aeration. "The more air is flowing through there, the better the site operates. That air flow also decreases smell and keeps away varmints," explains Paul Anderson, DVM, veterinarian in charge, Swine Diseases Division, state board of animal health.

* Monitor temperature continuously. Using a probe, ensure temperature is at least 130 degrees F; piles can heat up to 150 degrees F.

"If the temperature drops, the layers are improperly placed or something else is wrong," says Denkinger. To ensure pathogen reduction, compost piles must go through at least two heat cycles of greater than 130 degrees F.

Make sure to turn the composting piles every two to three weeks, emphasizes Anderson. "This is like stirring the pot. It maintains air flow, keeps animal parts evenly distributed and speeds completion of the composting process." Piles should be turned four or more times.

* Maintain the composting facility. It should be in good repair, covered to keep out the elements. The floor should be impervious to leaks and rot resistant.

* Don't spread composted material until the process is completed. Ideally, most compost material will be ready to apply to land in 60 to 180 days, according to the state board of animal health.

On a wet basis, each ton of finished compost consists of about 1,000 lb. of dry matter, 20 lb. of nitrogen (4 lb. from ammonia), 2 lb. of phosphate and 6 lb. of potash.

Finished compost can also be used as a good "starter" layer for the next composting cycle, says Denkinger.

* Add fresh carcasses daily. Don't wait until they start to decompose.

* Practice biosecurity around the compost. Keep out traffic and avoid traveling from the compost directly to another farm.

Anderson points out that under emergency situations for composting large numbers of animals, the board may issue a special permit for a compost constructed without a roof if sawdust or other water-repelling material is used to get rid of excess water.

The board has developed a brochure on setting up composting. For a copy or questions, contact the Minnesota Board of Animal Health, 119 Agriculture Building, 90 W. Plato Blvd., St. Paul, MN 55107, or phone: 612/296-2942; fax: 612/296-7417.