Oats have been an important crop in Iowa. In addition to being a favored spring-planted companion or cover crop for forage seedings, they have historically been harvested as a cash grain crop. In recent years, as market demands and cropping systems have changed, oats are more often being harvested as hay or silage for livestock.
One of the important decisions producers must make when using oats for forage is when to harvest the crop. This decision has several implications. Early removal of the cover crop from a new forage seeding reduces shade and moisture competition; a benefit to the new forage seedlings. And, harvest timing affects the forage yield and forage feeding value of the harvested corp.
Producers often use visual traits of the developing oat crop when making harvest decisions. Figures 1, 2 and 3 illustrate some of the most commonly used visual guides.
The forage yield and forage feeding value of the harvested crop change as the oat plant matures through its growth stages. (See Figure 2 and Tables 1 and 2). Note that these changes occur relatively quickly. Producers are encouraged to consider the nutrient requirements of the livestock being fed as a guide to timing of their oat forage harvest.
For lactating dairy cattle, oat forages should be harvested as the first grain heads appear in a field (late boot stage). Oat forage at this stage will provide a feed with more energy and similar protein levels to late-bud alfalfa and similar energy but higher protein content than corn silage. Many producers harvesting oats for feeding to gestating beef cows will delay harvest until the dough stage, to gain slightly more forage yield.
Source: Steve Barnhart, Department of Agronomy