Maximize silage quality at harvest

INDIANAPOLIS – Whole-plant moisture, chop length and proper packing are important factors when harvesting and storing high-quality corn silage.

“Corn silage should be harvested between 65 percent and 68 percent whole-plant moisture,” said Karl Nestor, senior animal nutritionist with Mycogen Seeds.

“Determining whole-plant moisture accurately is important, as it is difficult to guess moisture content simply by visual observation. Proper harvest moisture level is dependent on the type of storage unit used.”

Proper moisture level. Proper moisture level varies based on storage type.

Forages with higher moisture levels (wetter) are better suited for bunkers and drive-over piles, while lower moisture (drier) forages are better suited for storage in upright silos.

The best lactation performance by dairy cows fed whole-plant corn silage occurs at 65 percent to 70 percent whole-plant moisture.

This range in moisture content works well for achieving good preservation in horizontal silos. Silage for storage in upright silos may need to be chopped a bit drier than 65 percent moisture to minimize seepage.

“If silage is chopped too dry, it can be more aerobically unstable during feedout, as well as more challenging to chop and pack,” Nestor explains.

“In comparison, harvesting silage too wet increases the potential for greater dry matter loss. Wet silage will also have a higher acid content and a lower pH than drier silage. It is generally better to harvest corn earlier rather than later. However, it is not recommended to attempt harvesting silage above 70 percent moisture.”

Chop length. Chop length and proper packing are essential chop length is another important aspect of proper silage harvest.

Silage harvesting equipment should be set to attain the desired chop length.

This is called theoretical length of cut (TLC). Particle size at harvest will be affected by knife sharpness, harvest speed, shear bar setting and crop moisture. Drier materials will need to be cut shorter to ease packing.

Packing. The final step in producing quality silage is the proper packing of the harvested material.

Proper packing provides the environment necessary (anaerobic, or oxygen-free) for effective fermentation to occur soon after harvesting is complete. Silage that is more densely packed will have reduced dry matter loss and higher feeding quality than less densely packed silage.

It is also important to adequately cover stored silage to reduce or prevent spoilage.