Herd management

     Properly composting animal carcasses may be less of a threat to groundwater than burial or unattended surface dumping, says William Graves, University of Massachusetts extension professor of veterinary and animal science.
     Composting is the second best method of disposal, after rendering, and better than burial, Telega says.
     “The worst option is what I think is happening the most—dragging the carcass up into the woods,” says Telega. “There are two issues about this: Letting scavengers take care of your mortalities runs the risk of transmitting diseases to local wild animals and possibly back to your herd. The other is environmental. How close is the carcass to a stream, sink hole or whatever?”
     Graves has researched composting large animal carcasses. And Williams is currently conducting research on composting calves with funding from the Pennsylvania Association of Sustainable Agriculture. Both men see composting as cost-effective and environmentally sound. And when done right, composting creates little odor and makes some fertilizer.

Composting done right. For large carcasses, Graves suggests:
     1. Check with your state’s environmental agency or state veterinarian before you begin composting dead cattle. The Massachusetts Department of Environmental Protection, for instance, does not require a permit. Nor does Pennsylvania. Its law lists composting as one way to dispose of dead domestic animals. The Maryland health department still recommends burying. According to a Maryland source, composting is a “sleeping dog” issue that may be better handled quietly.”
     2. As an underlying layer, or substrate, use a mixture of hay, manure and bedding with moisture content between 40 to 50 %. “Remember that when carcasses are added you are adding water,” Graves says. “A 1,200-pound cow has the equivalent of 780 pounds of water in her tissues. This is the equivalent of 90-plus gallons of water.”
     Odor can be kept to a minimum as long as the pile is turned to aerate it and the covering material has enough carbon source, such as straw, sawdust or hay, to provide a 25:1 ratio of carbon to nitrogen (manure), Graves says.
     3. Construct a windrow 10 feet wide by 4 feet deep of the dry manure and bedding mixture. Locate it on a solid spot where the ground slopes 1 to 2%. Site it lengthwise with the slope of the land so runoff and snow can’t puddle against the windrow. If possible, orient the windrow north to south so that only one end faces a cold exposure. Choose an area where tractors can maneuver in all weather.
     4. Once you’ve placed a carcass, cover it with at least 2 feet of the same manure and bedding mixture that is underneath the carcass. Maintain a stockpile of the material for covering. Carcasses can be added anytime but should be spaced about 4 feet apart.
      5. The pile must heat up for proper composting. Use a compost-style dial thermometer, ideally with a 30-inch long probe, to monitor the temperature. Temperatures around the carcass will rise to 150 to 160 degrees. Monitor temperatures every two to three weeks. When temperatures fall to 110 to 125 degrees, stir the material with a bucket loader, allowing oxygen to re-activate the composting. “It is truly a cooking process, not a rotting process,” Graves says.
     6. Left untouched, an adult carcass will compost in five to six months. Stirring the mix and covering the carcass again can accelerate the time.
     Colder temperatures slow the compost process. When the air temperature is above 50 degrees and the pile is turned when its temperature drops below 120 degrees, the soft tissue in a 1,500-pound cow will finish composting as quickly as two to three months.
     There will be less bony residue with younger carcasses. Calves, for instance, may compost in three to four weeks under summer conditions.
     In areas with heavy rainfall, the process can be slowed if there’s too much moisture, preventing aeration, Graves says. Anchor a tarp over the windrow or mix some very dry sawdust or shavings into the substrate.
     7. When you see no more soft animal parts, you can spread the compost or leave it in place. Bones, which degrade very little, can be pulverized to spread on fields, creating good fertilizer. Or they can be left in the pile.
     Composting bacteria don’t work well on the contents of the rumen because they’re wet, Graves says. Stir them with drier materials to complete the composting.
     In his research, Graves applied finished compost to fields where corn was to be planted, then rebuilt the windrow. Although the windrow was located within 200 feet of a freestall barn at the University of Massachusetts farm, no one complained about odors. “Occasionally, a skunk would dig into the pile, but dogs and coyotes never were attracted,” he says. “Visitors to the university farm never were aware of our composting until informed.”
     To Williams’ thinking, a major advantage to composting is its convenience. “If composting can be made easier than whatever producers are doing now, it will take off.”
     Composting, done correctly, is an environmentally sound, economic way to dispose of animal carcasses.

Composting calves
     As part of his research project, Craig Williams, Tioga County, Pa., dairy extension agent, has compost piles on nine farms in three counties. He used 16-foot wire cattle panels to make 8-by-8-foot cages to contain sawdust compost. Cost was $40.
     “The reasons I used the wire panels was to avoid scavengers and contain the compost,” Williams says. He laid hay up a foot or so on the sides to keep the sawdust from filtering through the panels.
     Williams used straight sawdust, experimenting with both wet and dry, at a cost of $20. Following NRAES recommendations, Williams put 2 feet of sawdust on the bottom, layered dead calves on it, then added a foot of sawdust. The layers can be repeated, alternating calves and 1 foot of sawdust. Add more than a foot of sawdust around the sides of the compost, Williams says.
     He covered his compost piles with a plastic tarp to keep moisture out. “If it’s really, really wet, whether you use sawdust or manure and spoiled silage, a compost pile won’t heat as well,” he says.
     Williams used a 2-foot thermometer, ordered from Wisconsin-based Gempler’s, to track temperatures. Core temperature should reach 145 degrees, he says. “Four months is adequate time to compost a calf. In the winter if you don’t add calves, which are the nitrogen source, the heat core gets smaller.”
     Williams wants to keep the process as simple as possible so producers will compost. “If they don’t have to turn the pile every month, it will be easier to compost.”
      The $60 Williams spent is quickly recovered. “If it costs $8 per calf for renderer pick up, it takes only seven calves to pay for the wire panels and sawdust.” Also compost piles don’t require wire cages and sawdust. You can use materials on hand, such as manure, spoiled silage and bedded pack waste.
     Locate a compost pile conveniently, yet in an environmentally sound place. On the Doug and Scott Lawton farm near Wellsboro, it’s hidden by a cornfield but near the heifer barn, making it a quick trip to dispose of calves.
     The Lawtons, who participate in Williams’ research, have disposed of several calves successfully since April. But for the carbon source, they may switch to bedded pack material from sawdust, which they don’t regularly have on hand.
                                                                                                     –By Eleanor Jacobs

Learn about composting
     Since composting has been used in the poultry and hog industries to dispose of mortalities, ample information is available on the practice.
     • Field Guide to On-Farm Composting, NRAES-114 publication. Contact NRAES for a copy and the cost of the field guide: 152 Riley-Robb Hall, Ithaca, NY 14853. (607) 255-7654. E-mail: NRAES@cornell.edu. Web site: www.NRAES.org
     • Composting Dead Livestock: A new solution to an old problem, an Iowa State University Extension publication. (515) 294-4576.
     • William Graves at (413) 545-5577 or 2340. E-mail: wgraves@umext.umass.edu.
     • Penn State poultry extension specialist Paul Patterson, (814) 865-5691, and Lancaster County, Pa., extension agent John Schwartz, (717) 394-6851.
     • Craig Williams has composting tips gathered from his research program and is interested in gathering more information from dairy farmers about methods to dispose of mortalities and any experience with composting. Contact Williams at (570) 724-9120. E-mail: JCW17@psu.edu