New corn silage and a higher fat percentage in milk

Several of our customers have reported a higher fat percentage in milk due to switching to new corn silage – and with good reason.

A link is often seen between starting off with using the new corn silage and a higher fat percentage in milk.

This can be due to:

- the starch in the new corn silage being converted to a lesser degree in the rumen, thus forming less propionic acid to the benefit of the rumen’s pH balance, and higher fat percentage
- that the cow converts a lot of the corn fibres. On analysis results, this is called ‘Dig. NDF’ (Digestible Neutral Detergent Fibre). The rumen environment is improved when a large amount of fibre is digested, which increases the fat percentage.

How can grain be used as a supplement?

The starch in newly-harvested corn silage is digested more slowly and puts less strain on the rumen than corn silage that has been in the silo since last year. Fresh corn silage can therefore be advantageously combined with rolled grain, which is easily broken down in the rumen.

Over the summer, when the corn has been in the silo for 6 months, the starch is more accessible, and can therefore be advantageously combined with caustic treated wheat, which puts less strain on the rumen. If sodium bicarbonate combined with rolled grain is used, remember to stop if switching to caustic treated wheat. The high content of sodium in caustic treated wheat, and its buffer effect, mean that sodium bicarbonate should not be used.

When using sodium bicarbonate or caustic treated wheat, the mineral supply ought to be checked to ensure the correct amount and ratio between sodium and chloride.

If you have any questions concerning the use of corn silage and supplementing with grain, contact a Vilomix cattle consultant here​