Optimum weather conditions have dried out fields and corn silage producers have begun harvest.

Most dairy farms will harvest corn silage or alfalfa hay this month.

Crop production stored this month may not be fed for several months.

If the storage structure is in disrepair, there might be some feed loss due to spoilage.

Most corn silage is stored in upright vertical silos. However, larger dairy farms and feed lots often use bunker-type silos.

Corn moisture at harvest is a key ingredient to quality feed.

Harvesting at the optimum moisture level results in better quality feed. However, many times it will depend on the type of storage structure being used.

For sealed airtight silos, the ideal range is 60 percent to 65 percent; for upright silos, 63 percent to 68 percent; for silage bags 60 percent to 70 percent; and for trench silos, 65 percent to 72 percent moisture is the desired range.

Chopping at higher moistures often causes too much acid production (which reduces palatability), DM loss and seepage.

Valuable nutrients will be lost from the crop through seepage, which also can harm the environment.

Ideally, one should test moisture during harvest to stay within the optimum moisture range.

If this is not practical, you can monitor moisture by the stage of crop development.

A simple method can be used to determine the optimum stage for harvesting your corn silage.

When the kernels reach early dent state, a separation can be seen between kernel starch and milk.

Take an ear and snap it in half.

You can see the firm starch deposited in the outer part of the kernel while the milk will occupy the base of the kernel. This gives the appearance of a whitish line separating the two areas.

The milk line moves down the kernels as the kernels continue to mature.

When this line reaches the midpoint, 90 percent of the kernel dry weight has been achieved.

When the milk line reaches the base of the kernel, a black layer forms separating the kernel starch from the cob; the crop is then mature.

When the crop reaches full dent and the milk line first appears, the crop is usually about 70 percent moisture.

When the milk line reaches the midpoint, silage yields should be at their maximum and the moisture is at 65 percent.

When the milk line reaches the base of the kernel, the crop moisture is usually about 60 percent.

By observing the development of the milk line, one can determine optimum harvest time.

The one limitation of this method is the weather variation.

If you have experienced extremely wet or dry conditions for a few weeks before harvest, the moisture can vary by as much as 5 percent from the predictions given above.

There are also wide variations in hybrids, so testing is still important.

Luke Fritz is executive director of the Butler County Farm Service Agency.