Bill Weiss

Dept. of Animal Sciences

OARDC/OSU, Wooster, OH

Alfalfa stands suffered severe winter kill and heaving in many areas of Ohio. Because of these losses, many producers may be short of forage this spring and summer. Some producers may want to consider harvesting small grains for forage rather than for grain. All small grains (oats, barley, wheat, rye, and triticale) make acceptable forages for dairy cows when they are harvested at the proper stage of maturity. Small grain hay is difficult to make because of the long curing time necessary. Chopping small grains for silage is the preferred method of harvesting.

Nutritional Value and Yields

When harvested at similar stages of maturity, the nutrient composition of the different small grains is similar, i.e., maturity affects composition more than does species. The nutritional value of small grain forage declines rapidly with increasing maturity. Small grain forage harvested in the preboot stage has about 20% crude protein (varies with how much N fertilizer applied), 40% NDF, 30% ADF and in vitro digestibility of about 80%. Compared to corn silage, small grain forage harvested in the boot stage has energy concentrations similar to corn silage but greater concentrations of crude protein (CP). Small grain forage (boot stage) has more energy and about the same CP content as high quality alfalfa. At the milk stage, CP averages 12%, NDF averages 48%, ADF averages 35% and in vitro digestibility averages 62%. In the milk stage, small grains typically have about 10% less energy than corn silage but 3 to 4 percentage units more CP than corn silage. Compared with alfalfa, milk stage small grain forage has about the same energy content but lower CP. When harvested in the boot stage, dry matter yields should range between 1.5 and 2.5 tons per acre. When harvested at the milk stage, yields range from 3 to 4 tons per acre.

Harvest Management

Harvesting small grain forage at the proper stage of maturity is critical when the forage will be fed to lactating dairy cows. Rye should be harvested no later than boot stage and preferably in the preboot stage. Rye that has headed contains chemicals (not measured by routine forage analyses) that greatly reduce feed intake by dairy cows. Triticale should be harvested in the boot stage (less than 25% of the field has visible heads). Triticale seed heads are unpalatable and may reduce intake. Oats, wheat, and barley can be harvested in the boot to milk stage. When small grain forage will be fed exclusively to dry cows and heifers, rye should be harvested in the boot stage, triticale in the milk stage, and oats, wheat and barley in the dough stage. Intake is not as critical for dry cows and heifers and delaying harvest increases yields.

Milk Production

Most studies have found that small grain forage harvested at the boot or milk stage will support 50 to 65 lbs. of milk when fed in properly balanced diets. Diets based on small grain forage harvested at the milk stage requires more concentrate supplementation (energy) than corn silage-based diets. Alfalfa-based diets and diets based on small grain forage (milk stage) require about the same amount of supplemental energy. Protein supplementation should be based on the forage test. Some research suggests that cows fed diets based on small grain forage respond well to rumen undegradable protein (bypass protein). Small grains are typically low in calcium, moderate in phosphorous, and high in potassium. Mineral supplementation should be based on the forage test.

Conclusions

Small grains harvested in the boot to milk stage and stored as silage are acceptable forages for dairy cows. Farmers should have the forages tested and balance the diet according to the test results. Yields are typically lower than alfalfa or corn silage. Small grain forage harvested in the boot stage is similar in energy to corn silage and similar in CP to alfalfa. At the milk stage, small grain forage has about 10% less energy than corn silage (similar to alfalfa) and about 4 percentage units more CP than corn silage.