May 24, 2001

Manage Silage To Provide Nutrients to Dairy Cows

With haylage crop harvest approaching, good silage management will ensure dairy producers that the result of their labors is a quality feed, says a North Dakota State University dairy specialist.

"The first key to success is to make sure all equipment is operable and ready to go," says J.W. Schroeder of the NDSU Extension Service. That minimizes breakdowns and insures a timely harvest."

The second key step is to determine the optimum timing of harvest. "Timing is critical as forages may pass from desirable to undesirable in only a week," Schroeder says. "The stage of crop maturity at harvest is the most important determinant of the forage quality."

As the crop matures, dry matter (yield) increases and digestibility decreases, he explains. Depending on the group of animals to be fed, the appropriate stage of maturity at harvest differs. The typical stage of maturity for milking cow diets is the late boot stage for forages and first flower for legumes. Plants at those stages provide adequate yield and digestibility for milk production. For dry cows, replacements, and beef cattle a later stage of maturity would provide adequate nutrition.

Schroeder says that, ideally, harvest should be done as rapidly as possible. "The most important step in this process is rapid packing of the silage," he says. "During successful fermentation, bacteria in the silage convert sugar in the plants into acid that lowers the pH of the pile. If slow or improper packing results in too much trapped oxygen in the pile, it combines with the sugar to produce carbon dioxide, water and heat. That combination makes the silage unstable and delays fermentation.

Cover the silage pile after packing to prevent rainfall from entering, Schroeder advises. Runoff from rain in the pile results in loss of soluble nutrients (those most easily digested by cattle) from the silage. In addition, rainwater opens small pathways which allow oxygen to enter, causing spoilage and lowering silage quality.

The silage mass should not be disturbed for at least 21 days so the fermentation process can be completed and the silage can stabilize. Also, if the process is not completed, more rapid heating occurs during feeding.

"Management continues to be important when feed-out starts," Schroeder says. "To minimize the effect of oxygen exposure, at least 6 inches of material off the silage face should be fed every day. If it takes more than one day to feed across the silage face there will be increased losses, equal to or greater than the losses with fermentation."

Producers should plan pile sizes to accommodate this feeding rate.

"The process of fermentation to preserve forages can result in loss of nutrients. Good silage management will minimize the loss and provide the most nutrients possible to your dairy cows," Schroeder says.

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Source: J.W. Schroeder, (701) 231-7663, jschroed@ndsuext.nodak.edu
Editor: Tom Jirik, (701) 231-9629, tjirik@ndsuext.nodak.edu

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