Silage

Overview and Production 

Silage is a preserved forage produced by anaerobically fermenting high-moisture crops to retain nutrients and feed value. The practice of ensiling dates back more than 3,000 years to ancient Egyptian and Greek agricultural systems, where early forms of forage preservation were documented. 

Today, silage is a cornerstone of forage-based feeding systems in many livestock operations, particularly in dairy and beef cattle production. It is fed year-round in confinement systems, often forming the base of total mixed rations (TMR) due to its high energy content and digestibility. 

Silage is commonly stored in upright silos, horizontal bunkers, silage bags, or individually wrapped round bales. The most widely used crops for silage include: 

• Corn silage is valued for its high yield and energy density. 

• Sorghum and sorghum-sudangrass are favored in drought-prone areas. 

• Alfalfa and other legumes offer higher protein content but require careful moisture management. 

• Small grains such as oats, rye, barley, and triticale are becoming increasingly popular in double-cropping or cover-crop systems. 

In 2023, US corn silage production exceeded 130 million tons. Wisconsin, California, New York, and South Dakota led in total production. Iowa ranked fourth in corn silage acreage, with approximately 380,000 acres harvested, and fifth in production, with 7.6 million tons produced. 

Harvest timing is critical to silage quality. Crops are typically harvested at 60–70% moisture, though the optimal range can vary depending on the species and intended storage method. Proper packing and sealing of silage storage are essential to exclude oxygen and promote lactic acid fermentation, stabilizing the forage and preventing spoilage. 

Market  

Silage is more commonly grown and used on-farm due to its weight and storage needs but can be custom harvested or purchased under local agreements. While not a global commodity, silage plays a critical local and regional role in feed security, especially in states with large dairy or beef cattle populations. Producers managing forage budgets often weigh tradeoffs between homegrown silage, purchased or grown hay, and commodity feed sources. 

Useful Links, Background Information, and References 

2023 National Forage Review, 2023, Progressive Farmer 

Corn Silage Acres, 2025, USDA NASS 

History of Silage, 2003, Silage Science and Technology  

Figure 6: Corn ear at ~50% milk line, a good indicator it is ready to be harvested for silage.  

Figure 7:  Standing corn silage just before harvest.