With the hoopla over distillers grain as a less expensive option to high-priced corn in Western livestock rations, several University of California farm advisors have weighed in on the nutritional aspects of the byproduct from the ethanol production process.
UC Dairy Farm Advisors Alejandro Castillo (Merced and Stanislaus Counties) and Gerald Higginbotham (Fresno and Madera Counties) recently penned a newsletter called “Dairy cows' nutrition: the corn grain dilemma,” which offers insight into grain and the distillers grain issue.
According to the newsletter, four important points should be considered to best use grains for lactating dairy cows.
Protein content: Distillers grains are a good source of rumen undegradable protein. Degradable and undegradable protein contents should be used to avoid a shortage of nitrogen in the rumen. Lysine is the first limiting amino acid in corn byproducts and is the most susceptible to heat damage.
For that reason, lysine balances and insoluble nitrogen content should be evaluated to be sure that nitrogen and lysine are available for rumen microorganism and cows' metabolism. Positive results on milk protein content were observed when diets including distillers grains were supplemented with lysine in lactating animals.
Fat content: The effects of oils and fats on rumen fermentation can vary, depending on other feedstuffs used. Adverse effects might be more likely when diets are based on corn silage or high fiber diets. Fat may have effects on rumen fermentation by reducing dry matter intake. In most situations, total dietary fat should not exceed 6 percent to 7 percent of dietary dry matter.
Mineral contents and balances: Sulfur should be monitored as sulfuric acid and is initially added in dry grinding at ethanol plants and to end the fermentation process. Excess sulfur in dairy diets may affect absorption of other minerals such as selenium and copper, decreasing animal performance, and in some situations affecting animal health and reproduction.
Distillers grain may be offered dried or wet: Due to post-fermentation problems, and depending on weather conditions, wet distillers grains (WDG) should be stored no longer than seven days. Also, a high concentration of mycotoxins could be expected if the original grain was contaminated. Propionic acid or other organic acids, or mycotoxins sequestering agents, should be used to control mycotoxins as necessary.
Storage in silo bags could be an option, but once opened, spoilage starts. It is expensive hauling wet distillers grain long distances. Due to the high water content, rations may be too wet, affecting daily dry matter intake.”
Castillo and Higginbotham said no more than 15 percent to 20 percent of a lactating cow's total ration, on a dry matter basis, should be composed of distillers grain.
“The recommended inclusion rate for replacements and dry cows is 10 percent to 15 percent. Excess protein and minerals in the diets may be related to animal health problems and environmental concerns such as air and water quality,” the researchers said.
They urged dairy farmers to develop a plan with a nutritionist before including distillers grain in dairy rations.
“A complete chemical analysis of each distillers grain lot coming to a farm is fundamental to make a good use of this corn byproduct,” they said.
In results from a 2004 survey conducted by Castillo of Merced County dairy farmers, less than 50 percent of dairies were utilizing dried distillers grain. One hundred percent of the dairy farmers fed corn to lactating animals; the average intake was 8.2 pounds per cow per day, while the range was 2.4 to 15.6 pounds.
Meanwhile, Juan Guerrero, UC livestock specialist for Imperial and Riverside counties, says feeding WDG to livestock is a no-brainer.
“It cheapens the feed ration. If you can substitute for corn, then the mill doesn't have to run and you'll really be able to bring down feed costs.
“It's a great feed, high in protein, and well-priced. Because it's dry in this climate means it will keep, and the feed value is tremendous. You still need some corn, so you shouldn't replace it all.”
For feedlot rations, 20 percent to 25 percent of total dry matter can be fed as WDG, Guerrero says.
Hot summers in the southern valley would require feeding WDG daily, he notes. Mold problems could occur if the product is stored.
“The product is 60 percent to 65 percent water. Once it's exposed to air in these warm climates, it will mold quickly.” Cattle growers within 40-60 miles of the plant, who can get daily shipments, have the greatest advantage.
Asked about the prospects of growing corn in the valley to supply the ethanol plant at Calipatria, Guerrero said heat and other desert conditions can take a big toll on corn.
“With 5 percent to 6 percent humidity and strong, dry desert winds in April and May, the corn tassel containing the pollen is just fried. As a result, you can have a 10-foot to 12-foot high plant and one comb per plant. That's a disaster.”
Growing milo (grain sorghum) in the area holds more promise, he says.
“We're conducting research right now that's focusing on corn, triticale, and grain sorghum in different water regimes. In this climate, we think milo will be an option,” Guerrero says. “We will be growing them in different water regimes because corn takes a lot of water. Milo requires about 20 percent to 25 percent less water than corn.” Yield per acre and starch amounts will also be measured.
The UC Desert Research and Extension Center (UCDREC) at Holtville, Calif., is the location of the research efforts. Rick Bottoms, UC agronomy farm advisor and UCDREC director, is conducting the research with Guerrero.
“Water transfer to San Diego from the Imperial Irrigation District has made water efficiency and water use very important topics in this area. All crops grown must be water-efficient or be cultivated with water-efficient methods,” Guerrero says.
Growing milo in the warm climate desert is more natural and friendlier to water supplies, the farmer, and the environment. He says milo is better for the Imperial and San Joaquin Valleys.
As for tolerance to desert heat, Guerrero says, “Milo is like bermudagrass and Kline grass — when it gets to 115 degrees, it says ‘Give me more!”.