The newest method of estimating forage quality can help West Texas forage producers command higher prices from the dairies they serve, according to Dan Undersander, University of Wisconsin extension forage agronomist.
Undersander was a featured speaker at a forage management workshop in Plainview, sponsored by the Texas Alliance for Water Conservation and Texas Cooperative Extension.
"Relative feed value or RFV has been the quality standard for many years," Undersander said. "In 2001, the National Research Council Requirements for Dairy Animals recommended a new standard, relative forage quality or RFQ. It uses a summative equation for total digestible nutrients rather than estimating total digestible nutrients from acid detergent fiber to get RFV."
RFQ is an appropriate and accurate energy estimate for several feedstuffs, including those grown on the Texas Plains.
"RFV was a good value but we can do better now," he said. "RFQ is calculated on fiber digestibility. It helps you understand the quality of your forage so you can command a better price from customers who demand quality; customers like dairy operators.”
Sorghum silage could be an economical and profitable crop if forage producers choose hybrids high in fiber digestibility and consistent in quality.
"You can complement high-quality sorghum silage by double-cropping triticale or wheat for silage," he said. "Small grains produce tonnage efficiently without much irrigation. This saves water that can later be used on a summer sorghum silage crop. Both crops are also suitable grazing crops for calves and heifers.
"When you harvest forages for dairy use, remember that quality relates to intake. Milk cows prefer the highest quality. So you should harvest at the correct stage. Cutting earlier for quality means less tonnage. As a result, you need to get a premium for high-quality forage that will offset less tonnage from cutting early."
Growers who plan to market silage or hay should also understand their harvesting and storage losses. Haymaking losses generally range from 10 to 20% of crop dry matter, while silage harvesting losses are often less than 5%.
The flip side is that storage losses are higher for silage than for hay. Hay storage losses are typically less than 5%.
"Storage losses for silage generally run 15-20% of dry matter, so the value of your silage needs to be 15-20% higher than green-chop from the field if you are to break even on a per-acre basis," said Undersander. "You also need to figure in the cost of storing silage.”
Limiting ash content is also important in producing forages with high RFQs, he said. Data from the University of Wisconsin Marshfield Soil and Forage Analysis Laboratory indicates that higher ash content lowers total digestible nutrients.
"Ash is essentially soil contamination," he pointed out. "There are simple steps we can take to minimize ash in our forages: adjust your mower blades correctly, lay windrows on crop stubble, and rake the forage, not the ground.
"If you plan to market to dairies, remember that they depend on consistent supplies of high-quality forage to maintain milk production levels," Undersander added. "That's why top-quality, high-energy forage products command a premium in the dairy market.”