As the number of dairy cattle in Texas High Plains grows and the state ranks as the fourth-largest dairy state in the nation, Texas A&M AgriLife Extension Service teams are looking for ways to make sure the expanding herd gets fed.
Canola being grown by the Texas A&M AgriLife Extension Service in a study about forage value. (Texas A&M AgriLife photo by Jourdan Bell)
One recent study identified the forage value of canola, which may offer producers a high-protein feed alternative as well as another winter crop to consider for filling a spring forage gap.
Juan Pineiro, DVM, AgriLife Extension dairy specialist, and Jourdan Bell, Ph.D., AgriLife Extension agronomist, both in Amarillo, began looking at the nutritive value of canola in 2020.
“Feed prices are incredibly high this year, and protein concentrates such as soybean meal are usually the highest priced feed,” Pineiro said. “If you start a ration at a dairy with a forage source high in protein content, that means you have more opportunities to save money on buying protein concentrates.”
In addition, he said, there is an added benefit that if canola is harvested at an early stage, not only would the protein content be higher, but also forage digestibility would be better.
Growing dairy herd
The Texas dairy herd has basically doubled in size in the past two decades, Pineiro said, with the majority of those cows located in the High Plains region. The milking herd in the High Plains includes about 475,000 cows; the state’s total is about 625,000 head.
This is prompting growth in processing capacity, as four new plants are being planned or built to receive milk from the High Plains region. This will serve to keep dairy cow numbers high.
The U.S. Department of Agriculture statistics show Texas and New Mexico combine to produce about 10% of the U.S. milk supply, with about 80% of that amount produced in the High Plains of Texas and Eastern New Mexico.
Canola as a potential feed
In the Texas High Plains, corn has traditionally been the silage of choice, but as irrigation capacities decline, livestock producers are evaluating alternative forage options. And while research at Amarillo has proven that forage sorghums are ideal for water-limited conditions, there can still be a forage gap, especially under drought conditions.
Wheat, rye and canola can provide producers a winter and spring forage option to fill that gap, Bell said. Canola is typically produced as an oilseed crop, but research shows it can produce a high-quality forage, both for grazing and as ensilage, depending on growing conditions.
Canola forage can range anywhere from 16% to 10% in protein at flowering to early ripening, respectively, which is in line with wheat at 16% at boot and 10% at soft-dough. However, at flowering, the increased digestibility of canola would result in more feed intake and milk production.
“As with other forages, nutritive value is closely tied to the agronomic management, crop maturity and growing conditions,” she said. “While there is limited canola planted for oilseed production, in recent years canola silage, or canolage, has continued to expand in the western Texas High Plains as an alternative forage option for dairies.”
Data from research conducted in 2021 demonstrated that September and February planting dates could provide producers planting flexibility when growing canola as a forage in the Texas High Plains.
Another benefit of looking at canola as a forage crop is it can be double-cropped under some conditions. The production potential of double-cropped systems is limited by environmental conditions and irrigation capacity. However, it is a winter crop, so unlike summer forage crops such as corn and grain sorghum it can provide producers an opportunity to maintain a winter cover on a forage field while growing a forage source.
“Intensively managed forage fields are susceptible to wind erosion because little biomass remains after silage is harvested in the fall,” Bell said. “Winter crops like wheat, rye and canola can provide a cover as well as a spring forage source, but there is always a trade-off in semi-arid environments. The winter forage will use stored soil water and precipitation during the growing season. If there is not timely spring and summer precipitation, there is extra pressure on the irrigation systems in the summer or yield losses especially in drought years, like the current year.”
Research determines answers
In 2020-2021, canola forage yield and nutritive value were evaluated for one cultivar at the Texas A&M AgriLife James Bush Research Farm at Bushland on drip irrigation. Although previous canola planting date studies at Bushland identified September as an ideal seeding period for oilseed production, a late winter planting date was also evaluated in 2021 as a forage option.
Bell said the canola was planted on Sept. 24, 2020, and Feb. 1, 2021, on 30-inch rows at 500,000 seeds per acre. Total irrigation was 5.6 inches for the September planting and 3 inches for the February planting. The forage was harvested at flowering and the early ripening stages.
“As with other forage crops, data confirmed that canola forage yields increased with plant maturity,” she said. “Yields were greatest for the early ripening growth stage when pods were still green, and most flowers had dropped. But there was a decline in evaluated forage nutritive value.”
Crude protein decreased 6% from the September-planted forage at flowering to early ripening stage, Bell said. And the acid detergent fiber, ADF, and neutral detergent fiber, aNDF, increased as plants matured. The ADF is a measure of the plant cellulose, lignin and insoluble protein. The aNDF is a measurement of the fiber.
She said the lower ADF and aNDF are indicative of improved digestibility and forage quality. The relative feed value, or RFV, is an index combining NDF and ADF as a forage benchmark relative to alfalfa at full bloom assuming 41% ADF and 53% aNDF.
Also important to the dairy industry, the indices of net energy for lactation, NEL, and RFV suggested improved forage nutritive value for harvest at flowering. The RFV for the fall-planted canola at the flowering stage was 226, indicating a forage that would be classified as prime compared to alfalfa.
Bell said although RFV decreased 52% from flowering to early ripening, the RFV remained greater than 100. The forage nutritive value for the September 2020 and February 2021 planting dates at early ripening were comparable.
Management practices for highest quality
High moisture contents at harvest require canola to be swathed and wilted before ensiling, Bell said. Ensiling is a process that allows producers to preserve high moisture forages and maintain forage quality, but moisture contents greater than 70% increase the leachate or liquid seepage from the silage pile.
In addition to leachate concerns, high-moisture forages do not reach ideal lactic acid concentrations resulting in poor fermentation and risking the development of clostridial organisms, she said.
When cutting high moisture forages, producers should consider environmental conditions, potential forage shrink, and the desired forage quality including intake and nutritive value, Bell said.
Research at Washington State University demonstrated that blending canola forage with a lower dry matter feed source could minimize leachate loss.
“Canola forage may not be a stand-alone forage,” Bell said. “It is a high-nutritive value option that should be blended with other feed sources because it can have very low fiber and high protein.”
Another concern, she said, is canola can also be high in nitrates. While nitrates dissipate during the ensiling process, producers should always test the forage prior to feeding.
Another option is chopping and feeding canola immediately as green-chopped forage rather than ensiling.
As dairy herds increase, research is important to evaluate alternative forages for water-limited production systems, and the Texas High Plains region is currently under extreme drought conditions: https://droughtmonitor.unl.edu/.
Source : tamu.edu