Kansas swine nutritionist Joel DeRouchey presented a fast-paced lesson on swine nutrition research findings, feeding recommendations and industry trends in a 50-minute talk at World Pork Expo.
The Kansas State University (KSU) Extension specialist focused on ways pork producers could reduce their environmental footprint by altering feeding programs. A timely bonus was that many of the strategies also promised to lower feed costs.
Focus on feed efficiency
“The higher efficiency we have, the lower the excretion levels,” DeRouchey reminds. And, don't overlook the basics of efficiency, including using feeders designed to minimize waste, adjusting them often and using phase feeding or even specialized feeding software to match diets with the pigs' nutrient requirements.
He recommends reducing any safety margins built into rations. With today's high feed prices, balancing rations with extra nutrients to provide a cushion is costly, he says, but keep an eye open for the negative effects of inadequate nutrient levels, such as skeletal problems when finishing hogs don't get enough phosphorus.
Lower phosphorus excretion with phytase
When considering phosphorus requirements, look at available phosphorus vs. total phosphorus required for various growth phases. DeRouchey laments that many commercial swine diets today provide more available phosphorus than National Research Council's (NRC) suggested 0.15% and KSU's recommended 0.18% for late finishing pigs (over 200 lb.).
“We see diets come in at 0.25-0.26% (available phosphorus) in late finishing. They are spending way too many dollars on phosphorus.”
With the monocalcium phosphate (monocal) and dicalcium phosphate (dical) prices at $1,000/ton, other options should be considered, he says.
The enzyme phytase is a saving grace to assist in the digestion of the phytate phosphorus naturally found in feedstuffs. “If you look at phytase from an efficacy standpoint, it flat out works,” he declares. (See Figure 1. )
But there are some precautions when using phytase. Avoid confusion on inclusion rates by targeting phosphorus release values when formulating rations, rather than just looking at phytase units. Currently, manufacturers use different units for reporting levels in the diet. “Products should be compared on equal release values in the diets,” DeRouchey says.
To get the most cost benefit in rations, he recommends replacing about 0.10% available phosphorus with phytase (Table 1 ). Higher levels, up to release values of 0.12 - 0.15, can be used, but with less economic return. Phytase's ability to release phosphorus plateaus at higher levels, he explains.
Using phytase at the recommended 0.10 release value saves producers about $0.95/finishing pig.
“Some people have started to get themselves into trouble by taking phytase too far (beyond the 0.12 release value) and not recognizing its diminishing returns,” DeRouchey says. Trouble can include phosphorus deficiencies, such as rickets and broken bones, when phosphorus release is overestimated.
In most diets used today, even with phytase, there is still about 40% of phosphorus being excreted. “That's the opportunity,” DeRouchey says. Low-phytate corn is one option that may help increase phosphorus efficiency.
Remove fat and reduce feed particle size
Nutritionists traditionally recommend 600-800 micron particle size when grinding hog feed. But smaller particles improves feed efficiency and makes good sense — to a point.
“Returns are linear going from 700 to 300 microns,” explains DeRouchey. “The finer we grind, the more digestible the feed is. But we have to recognize if we grind too fine, we'll have added feed flow problems and a higher instance of gastric ulcers.”
Many producers are grinding to 600 microns or finer. “They are getting away with it because they no longer have added fat,” he contends. At $0.40 or more per pound for choice white grease, for example, added fat is simply too expensive to formulate into most rations, so he advises producers to pull the plug on added fat. Without the fat, finer grind diets are easier to manage because feed flows better through equipment.
Some producers are skeptical of removing fat from lactation diets, but doing so saves dollars, too. “Added fat in a lactation ration will typically yield a one-third to one-half extra pound per weaned pig,” says DeRouchey. “However, the value of that extra weight currently does not justify the added cost for many producers.”
Consider nutrient-rich corn
DeRouchey said that corn hybrids with NutriDense (BASF Plant Science) traits have higher concentrations and provide greater digestibility of key amino acids (lysine, threonine, methionine, tryptophan, isoleucine and valine) vs. No. 2 yellow dent corn. That means producers can feed less crude protein to reduce nitrogen excretion. Plus, NutriDense hybrids offer about 5% more energy, which helps improve feed efficiency and also helps make up for eliminating fat from diets.
To illustrate the cost benefits, DeRouchey cites a 2004 study evaluating average daily gain (ADG) and feed efficiency (FE) when zero, 3% and 6% added-fat diets (formulated with yellow dent corn) were compared with diets using NutriDense corn. Although adding fat currently is not economically feasible in most rations, the goal was to determine if the energy benefit from corn with NutriDense traits would be additive when fed along with added dietary fat.
The study showed that diets with zero and 6% added fat had a significant improvement in ADG when the diets included corn with NutriDense traits. With the zero added fat, pigs grew about 2% better with NutriDense vs. No. 2 yellow dent corn (1.83 vs. 1.80 lb./day). With 6% added fat, pigs grew 4% faster with NutriDense corn compared to yellow dent corn (1.90 vs. 1.83 lb./day).
In all three diets, the NutriDense-trait corn improved feed efficiency compared to No. 2 yellow dent corn diets. In diets with no added fat, pigs had a 7% improvement in FE (2.67 NutriDense vs. 2.87 yellow dent). DeRouchey figures the 0.2 lb. improvement in FE is worth $4.50/pig marketed.
NutriDense comes with a premium price tag, but Chris Peter, a BASF Plant Science field nutritionist, says the $4.50 advantage translates to about $0.50 extra value on each bushel of corn consumed per pig (9 bu./feeding period).
Use synthetic amino acids
DeRouchey says the use of synthetic amino acids jumped this past winter and spring as soybean meal prices skyrocketed. The move to lower crude protein levels results in a 20-40% lower nitrogen excretion and decreases ammonia production, thereby improving air quality. Recently, methionine prices have increased, so economics must be carefully monitored, he adds.
Consider distiller's grains
With a savings from $1.50 to $3.00/pig in feed costs, DeRouchey says many producers are opting to use dried distiller's grains with solubles (DDGS), where available. However, the alternative feed source does not have much effect on manure excretion.
Manure volume will go up because DDGS have more fiber and lower digestibility, but nutrient management planning and manure value are virtually unchanged. Nitrogen value is higher, but not significantly.
Since DDGS are a poor source of lysine, it figures dietary crude protein (CP) would have to increase, so nitrogen also jumps. DeRouchey says that can be mitigated by using synthetic lysine.
“On a 15% DDGS diet, CP increases about 1% when we maximize the use of synthetic lysine. Economically, there's no reason not to do that,” he says.
For a 2,400-head finishing facility using a 15% DDGS diet, with maximum use of synthetic amino acids, the annual nitrogen excretion goes up by only about 6,000 lb. (8%).
DDGS diets impact phosphorus excretion even less. While phosphorus excretion with DDGS diets can be a worry for beef and dairy producers, that's not a problem for swine producers, DeRouchey says. DDGS provide about 0.77% available phosphorus compared to just 0.14% for corn. DDGS combined with phytase means producers can decrease or remove supplemental dical or monocal in most finishing rations.
For the 2,400-head unit, phosphorus output is about 11,000 lb./year for either a 15% DDGS diet or a traditional corn-soybean diet, assuming phytase is used in each.
DeRouchey emphasizes that facility site planners developing manure management plans must use updated projections for manure concentrations and excretion levels based on current feeding regimens and expected manure output vs. common industry book values, which might reflect older feeding styles and animal profiles.