For maximum quality, most wheats and triticales should be harvested in the boot to very early heading stage. Depending on the variety and the weather, it may take only a few days for the crop to progress from boot to heading stage or it may take over a week. This period is a time of rapid changes for the crop, as dry matter yield increases dramatically but fiber digestibility declines. Once the crop is pollinated and kernels begin to accumulate starch, overall digestibility may increase again because of the contribution of the grain to the total dry matter.
At this time, In Vitro True Dry Matter Digestibility is not a measurement that can be used directly in a ration calculation, but is best used to compare fiber digestibilities between varieties or cutting dates within a trial. Information on very early cut Kanota oat and several other forages is given toward the bottom of the chart to help you make comparisons with a variety and maturity you may be more familiar with.
With the exception of Mortlock Oat, all the oats in the cutting date comparisons are late oats designed to be harvested in the late boot – early heading stage. Mortlock is an Australian oat that flowers before the plant has headed out. By the time heads emerge, it is already in the milk stage.
In this trial, there were significant increases in tonnage from delaying harvest by even a few days in most cases. As expected, fiber digestibility also declined. Whether the decrease in fiber quality is important depends on the particular needs of the dairy and the class of animal that is being fed. Dairies who are feeding high quality winter forage to milking animals will need to cut earlier than those who are feeding dry stock. Remember that ensiling any forage too wet may cause spoilage that will ruin even the best quality forage.
November 5, 1999