Understanding silage test results
Silage analysis is a vital part of formulating ruminant diets and is money well spent.
Testing your silage will give you information on the dry matter, how well it is ensiled and probably most importantly the feeding value.
Having your silage tested is one thing but you need to be able to understand the results. Below is a description of some of the common terms that appear on a silage test report.
Dry matter DM%
Most forage analysis results are expressed on a dry matter basis. This figure relates to how much water is present in the silage. The silage dry matter is also important when assessing preservation quality and predicting intake. Ideally the dry matter of pit silage and baled silage should be around 25 – 30%. Once the dry matter goes above this it makes it harder to ensile and it is also prone to moulds and spoiling once it is fed out. Higher dry matter will lead to higher intake.
Satisfactory ph values will vary with the DM of the silage. Unwilted silages should ideally have a ph between 3.8 and 4.2. ph values of 4.2 up to 5.0 may be acceptable for wilted silages. Low ph below 4 will have low palatability and animal intakes will also be low.
The DMD is an accurate and reliable test of forage feeding value. The DMD result is used to estimate the energy of the silage as well as expected liveweight gains and milk yields and also allows for calculation of supplementation rates.
Crude Protein %
Crude protein varies generally from 9 to 17%. The leafier the grass was at cutting the higher the protein % should be.
This is the amount of available energy that is in the feed. Like protein the energy value of the silage should be higher the earlier it was cut. Values range from 9 MJ ME/ kg DM for headed out grass to 12 MJ Me/kg DM for leafy grass.