By Mark Sulc and Bill Weiss et.al.
Winter cereal forage crop development is advancing with the early warm weather this spring. These crops include winter rye, winter wheat, winter triticale, and barley. Italian ryegrass planted late last summer to early autumn is another forage crop that is developing early and will be ready for harvest by late April. The cool-down this week will likely slow development of these crops, but producers should be looking ahead to be ready when these crops reach optimal harvest stages.
Forage yield and nutritive value of these forages can change rapidly as the crop matures (see table below). The optimal stage of harvest will depend on the livestock to be fed. As with all forages, yield and quality are inversely related and the user will need to choose the appropriate compromise between yield and nutritional value.
Figure 1
For lactating dairy cows or beef stockers, grass forage crops like these should be harvested when neutral detergent fiber (NDF) is less than 55%. To achieve this, cereal rye should be harvested no later than the boot stage and preferably in the pre-boot stage. Rye that has headed out 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 especially when fed as dry hay. Italian ryegrass should also be harvested in the late vegetative to early boot stage. Wheat and barley can be harvested in the boot to milk stages.
When forage will be fed exclusively to dry dairy cows and heifers, or beef cows, rye should be harvested in the boot stage, triticale in the milk stage, and wheat and barley in the dough stage, and Italian ryegrass can be in heading stages. Intake is not as critical for dry cows and heifers and delaying harvest increases yields.
Chopping and ensiling or wet wrapping bales are the best mechanical harvest alternatives for most of the winter cereals, as they contain high moisture content and are difficult to dry for hay, especially in the spring. Italian ryegrass can also be difficult to dry, but it depends on the stage of growth. Wilting these crops will be necessary before ensiling or wet wrapping bales. Ideally, silage/haylage should be left undisturbed for at least two weeks to allow the forage to reach stable fermentation. If forage is needed sooner, use silage bags or wet wrapping individual bales for feeding until the silage in bunkers is fully fermented.
Before feeding, test the forages and incorporate them into a balanced diet based on the test results. Studies with dairy cows have shown that cereal forages harvested in the boot or milk stages support more than 80 lbs of milk when fed in properly balanced diets containing less than 22% forage NDF concentrations in the diet. Diets based on cereal forage harvested in milk stage require more concentrate supplementation (energy) than corn silage-based diets. Alfalfa-based diets and diets based on cereal forages (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 cereal forage respond well to rumen undegradable protein (bypass protein). Mineral supplementation should be based on the forage test.
High levels of potassium in forage can be a problem, especially for dry cows. The high potassium inhibits absorption of magnesium, so the concentration of magnesium in diets based on grass needs to be increased to between 0.3% (lactating cow) to 0.4% (dry cows) of diet dry matter. High potassium diets fed to dry cows increase risk of milk fever which can only be mitigated by either feeding lower potassium forages or feeding supplemental dietary anions to reduce the cation anion difference. Consult a nutritionist to come up with appropriate supplementation. When grazing winter cereal forages or Italian ryegrass, supplement lush spring pastures with high-magnesium mineral blocks or mineral-salt mixes to reduce the risk of grass tetany.
Baled cereal forage often has a very large particle size, so consider how to reduce the particle size before feeding. Whenever possible, baleage from these forages should be made with a baler that has a cutter option. This improves bale density and fermentation along with feed out. When fed free choice using a hay ring, these long particles often result in increased waste. Processing these forages results in more complete digestion. If not cut at the baler, a tub grinder or vertical mixer can work well to decrease particle size. The Ideal particle size for most beef diets is a maximum of 5 inches in length.
Source : osu.edu