Producer/owner Bob Dykhuis (left), Kevin Kaiser, feed delivery driver, and Jay Flowers, marketing manager, work as a team to make sure pigs are fed an environmentally friendly diet. The diet program provides other health benefits to the pigs and allows better utilization of the pig manure.

What goes in must come out. In this case, the more precise the pig’s diet, the more environmentally friendly the manure becomes. This is something everyone has to deal with as local, state and federal governments continue to tighten environmental regulations.

“You have to meet the pigs’ needs by matching diets to pigs’ genetics, age and physiological stage,” says Gretchen Myers-Hill, animal scientist at MichiganStateUniversity. “All pigs don’t eat alike or absorb nutrients alike, which means the excess goes out in the manure.”

One producer addressing the environment through his operation’s feeding program is Bob Dykhuis, Holland, Mich. He uses phytase in all of his herd’s diets, except in the nursery. He doesn’t use it there because those diets are pelleted, and phytase activity greatly declines when heated.

Dykhuis also incorporates by-products such as wheat midds and distillers dried grains with solubles, bakery waste, liquid whey, cheese and yogurt. He varies by-product use depending on which ones offer the lowest prices.

Diets with a combination of by-products containing higher levels of available phosphorus compared to a typical corn/soybean meal/phytase diet, reduce the amount of phosphorus hogs excrete in manure. These eco-friendly diets allow Dykhuis to spread more manure per acre.

This focus is necessary for his expanding operation. By early 2006, Dykhuis Farms will market 300,000 pigs annually. The family corporation also farms about 1,900 acres of corn and soybeans.

Dykhuis feeds wheat midds to help make phosphorus in the diets more available to the pigs. He also buys liquid whey, along with other dairy by-products like cheese and yogurt, to add available calcium and phosphorus to gestation-sow diets. Yogurt and cheese provide added minerals, and reduce the inorganic-mineral sources that Dykhuis has to add to the diets.

“The dairy by-products save money and help balance phosphorus availability,” says Dykhuis. By feeding liquid dairy by-products he can reduce the total amount of dry feed that his sow herd consumes, and reduce the amount of inorganic phosphorus (mono-calcium or di-calcium phosphate) he has to add to the diets.  

“Once we started using phytase in combination with liquid dairy products in sow rations, we had a 30 percent to 40 percent decline in manure phosphorus,” he notes.

The deciding factors are still performance and costs. “It comes down to feed conversion,” says Dykhuis. “You can talk about using phytase and by-products, but pigs still have to convert feed efficiently, or it’s a waste.”

He also has seen an improvement in the health, management, nutritional and genetic responses of the pigs.

While phosphorus is grabbing more attention, you still have to work on reducing nitrogen. University of Missouri animal scientists have conducted studies that show you can reduce nitrogen excretion by properly formulating the pigs’ diets and adding the right amount of crystalline amino acids (lysine, methionine and threonine.)

“Economically, you can make these work, depending on the price of amino acids and soybean meal,” says Gary Allee, swine nutritionist, University of Missouri.

As a rule, for each 1 percent reduction in dietary crude protein, you can reduce manure nitrogen excretion by 10 percent without sacrificing cost or performance, he says.

“There’s a certain fear of underfeeding nutrients,” says Brandon Hill, a certified nutrient-management planner for Hamilton Farm Bureau Cooperative, Hamilton, Mich. “Most companies and producers have built in safety margins and look at least-cost formulations. However, it’s more comfortable to add a few pounds of di-calcium or mono-calcium phosphate in the mid- to late-finisher rations, instead of accounting for wheat midds, DDGS or other by-products that contain high available phosphorus.”

“It’s easier to overfeed than to test and secure consistent by-product sources,” explains Myer-Hill.

Another tendency to watch is feeding high levels of zinc oxide and copper sulfate in the nursery to promote pig growth and gut health. Those minerals can build up in the soil when nursery manure is applied to the land at excessive application rates or by continually spreading it on the same field.

The European Union has banned copper sulfate feeding levels higher than 30 ppm, and zinc oxide can’t be fed at levels of 3,000 ppm or higher. It’s common in the United States to feed young pigs copper sulfate between 200 to 300 ppm and zinc oxide from 2,000 to 3,000 ppm. 

The United States could see restrictions similar to the ones in the EU if negative environmental consequences from those minerals are tied to swine-manure applications and subsequent leaching or transport.

Therefore it’s critical to spread nursery manure over multiple fields and at proper rates so mineral build up does not occur.

Producers need to work with nutritionists, feed companies and university specialists to minimize safety margins in diets to meet a pig’s genetic potential, says Myers-Hill.

Different genetics require different nutrient levels, depending on performance, growth, sow productivity and carcass composition potential. It’s no secret that sow lines that farrow 12 pigs and are heavy milkers have different requirements than their less-productive counterparts.

While you can’t take a chance of getting phosphorus levels too low, you must account for the available phosphorus in your feedstuffs, says Myers-Hill. Be diligent about having your nutritionist account for all of the available phosphorus in diets.

Phosphorus demands decrease as pigs grow, yet mid- to late-finishing diets don’t always see the reduction or elimination of inorganic phosphorus. For the sow, it goes back to a fear of underfeeding and therefore affecting the bone structure or the potential for breakage. 

“You have to continually fine-tune diets just like a racecar,” says Myers-Hill.

You can accomplish a lot with diet formulation — and it’s often cost neutral,” says Allee. “Most producers would like to do everything that’s available to minimize any potential negative environmental effects.”  

To continue to make progress, the industry needs more data on nutrient requirements for today’s pigs; and producers need to properly account for the bio-availability of nutrients used in feedstuffs.

Buy By-Products Carefully

Using co-products or by-products, such as distillers dried grains with solubles, can increase the available phosphorus, reduce the total phytate phosphorus (unavailable phosphorus) in the diet, reduce phosphorus manure excretion and offer potential cost savings, says Gretchen Myers-Hill, animal scientist, Michigan State University.

To buy and feed by-products properly you need to:

  • Have the by-products tested consistently to determine their nutrient status.
  • Secure a quality supplier with a uniform product.
  • Give these by-products the nutrient values they deserve. This is especially important in terms of energy and available mineral status. 

Some companies put out consistent products, but others will vary. Myers-Hill says you need to take samples and have a reputable laboratory run the analysis. Find out how long the company has been in business and if it runs standards on the products.

Give Manure More Credit

Swine manure hasn’t gotten the credit it deserves, but that’s about to change. The American Society of Agricultural and Biological Engineers has revised a set of values that describe manure’s characteristics.

Rick Koelsch, University of Nebraska agricultural engineer, says the old values focused on animal size and manure-collection timing. The new ones include pig performance and diet influences.

Today’s genetics are much more efficient and produce leaner-muscled pigs, notes Koelsch. “There’s also a growing set of feed-management practices, such as using phytase and crystalline amino acids, that reduce nitrogen and phosphorus excretion,” he says. “By using these new (ASABE) values, we can adjust our nutrient-plan estimates by what the pigs are eating.” The new values also provide more accurate data to use in designing manure storage. Koelsch developed a spreadsheet to help work through “What if” scenarios such as what’s the impact of a 1 percent phosphorus reduction on manure excretion and land application. ASABE members can directly access individual standards through Non-members can order hard copies of standards from, request the “2006 ASABE Standard.” You also can access electronic copies through