Second Cut Silage

Second cut silage is typically more expensive to produce than first cut and quality also tends to be variable.  This has made second cut silage less common in recent years.

 

Good yields spread the costs of your silage over a greater tonnage. Quality is equally important dictating animal performance, be that milk production or recovering cow condition.

 

Below are the key factors in achieving good silage second-cut yields and quality:

Soil Fertility
Maintain soil P, K and lime levels based on up to date soil analysis. Organic manures are very useful in helping to balance P and K levels on silage ground. 

Nitrogen (N)
Apply circa 100Kg N/ha (80 units/acre) with high perennial ryegrass content swards (recently reseeded ground) requiring higher levels of N. Make sure you allow for any organic manures used. Apply all your fertiliser as soon as possible after the first cut and evenly as possible.

N fertilizer reduces grass sugar levels & increases buffering capacity, therefore allow enough time for any N applied to be utilized to ensure good crop preservation. Approximately 2 units of N per day are used up by the crop. Therefore if you spread 80 units/Ac; allow at least 40 days between N application and mowing. Note bad weather will reduce the uptake of N and more time may be required to reduce N levels.

Preservation aids
In order to preserve silage, lactic acid bacteria need high sugar levels (minimum 2.5%, preferably >3%), to ensure a rapid drop in pH and good preservation. Sugar levels tend to be erratic in crops depending on the time of day (highest in the afternoon/evening) and weather conditions (increase with sunshine and cool nights). But in general over time it increases as the grass crop matures, hence making low digestibility silage easier to preserve.  

 

Wilting is a useful preservation aid as it will help to increase sugar levels. Benefits are greatest after a wet spell but ensure the crop is reasonably dry before mowing (all dew disappeared) and spread rows of grass out over the field. There is no benefit in wilting crops for more than 24 hours prior to pick up. 

The use of an additive will help greatly in the preservation of young leafy crops or where N levels or sugar levels are not ideal. They are less relevant for relatively mature, wilted crops given adequate time to use any N applied.

Key point: Additives will help greatly in the preservation of young leafy crops or where N levels or sugar levels are not ideal

Pit management
Your aim is to achieve anaerobic conditions as quickly as possible and completely maintain until the pit is opened. This involves quick filling of the pit ensuring the grass is well compacted and sealing carefully beneath a double black polythene layer followed by a full covering of tyres and sandbags. Inspect frequently (at least once every two weeks) and immediately repair any damage to the polythene. At feed-out; try to move across the pit face quickly and evenly, preferably using a sheer-grab, to minimize heating losses.

 

Key point: Quick filling, good compaction of the pit and sealing carefully are vital to achieve anaerobic conditions and good fermentation.  Inspect the pit at least every two weeks and repair any damage immediately.