Milk-Line Can Maximize Productivity of Milking Line

Written by Brad Beatty, CCA

Corn silage harvest is underway in eastern Iowa.  To help ensure the best quality silage possible, watch the crop’s moisture content.

Optimal performance by dairy cows occurs when whole-plant moisture is between 65 and 70%.  This moisture range also works well to preserve silage quality in horizontal (bunker) silos.  However, corn may need to be chopped a bit drier when stored in up-right silos like Harvestores.  Moisture levels between 60 and 65% moisture can minimize seepage in up-right silos, but research shows that reduced fiber and starch digestion, along with reduced lactation performance, occurs when corn silage is harvested at 60% moisture or below.

The optimum 60 to 70% whole-plant harvest moisture corresponds closely with when the kernel milk-line has moved from one-half to three-fourths the distance from the kernel’s crown to the tip where it’s attached to the cob.  Click here for information on how to find the kernel milk-line.  

Once moisture of a hybrid is known, figure a corn plant will lose about 1% moisture daily. Monitor the milk-line to gauge whether the moisture is changing too fast.  It usually takes 12-15 days to go from early dent to 50% kernel milk and another 12-15 days to go from 50% kernel milk to black layer.

More corn silage harvest techniques are available online at

NOTE:  Milk-line and whole-plant moisture can vary between hybrids and across environments.  What Latham® Hi-Tech Hybrids are working well to make silage in your area?