Harvesting sprouted grain
By Alberta Agriculture and Forestry
Oct. 2, 2015 - Weather conditions this fall have been challenging for producers and have left many fields with sprouting grain, either in the swath or in standing grain.
"Sprouting has serious implications for end use and quality," says Harry Brook, crop specialist, Alberta Agriculture and Forestry, Stettler. "Under the grain grading standards, #1 wheat is allowed a maximum of 0.5 per cent sprouted kernels and 0.10 per cent severely sprouted kernels. #2 CWRS has allowances of 1.0 per cent sprouted and 0.2 per cent severely sprouted. #3 CWRS is allowed 3 per cent sprouted with no more than 0.3 per cent severely sprouted. If wheat is over these limits, it's only fit for feed."
With malt barley, sprouting maximums are very low; however, feed barley is allowed up to 10 per cent sprouted for #1 CW and 20 per cent for #2 CW barley. "Unfortunately, a lot of our swathed wheat and barley have very high levels of sprouting."
Brook says sprouted grain can cause a lot of problems.
"Using it for forage has issues. It needs to be dry to be baled and stored safely. Usually it is too wet for baling and too dry to be ensiled as a silage bale. As a baled feed, there are other challenges. This is not a greenfeed but a bale of straw and grain. When fed to cattle, they will sort through the bale, selecting the grain and picking at the straw. There is a very good chance of the cattle getting acidosis from ingesting too much grain. If it is dry enough to bale, it should be dry enough to combine. The best way to harvest sprouted grain is to harvest it with a combine when dry. To speed drying, using a swath inverter may help."
Right after physiological maturity, most grain has some resistance to sprouting and goes through a dormancy period. "However, high temperatures during the later stages of grain filling and maturity, as we had in August, can lower that resistance and make the grain more susceptible to sprouting. Furthermore, cool, moist conditions after maturity increase the likelihood of sprouting. Weathering of grain from wetting and drying cycles also reduces test weights, most likely due to the starch being metabolized by enzyme activity."
Sprouted wheat or barley, when feed to cattle, performs equally as well as whole grain, notes Brook. "There is no difference in feed efficiency or animal use. Bushel weights tend to be lower but it doesn't affect feed quality on a pound-for-pound basis."
Sprouted wheat loses some of the properties that makes it good for bread making. In the kernel, starch is broken down by enzymes and activated by sprouting, which affects falling number, a crucial measure of bread making quality. Energy from the starch is used by the seed to initiate growth of roots and shoots.
"Other than not having too much moisture in the fall, the best way to avoid sprouting is to harvest the grain tough, at 20 per cent moisture, then dry it down to safe storage levels," says Brook. "Reduce the chance of anything affecting the harvesting efficiency, and hope for warm, dry conditions to harvest under.
"Sprouting grain is an issue this year but the crop still has value from a feed perspective. Dry it down as quickly as possible and get it off the field to minimize the damage from this fall's weather."