Hit your grass silage target this season
Date: 15 September 2015
With lower dairy prices, it is essential to maximise the returns from your silage by following several key steps.
1. Harvest at the correct time.
The feed value of the ryegrass plant drops rapidly as it enters its reproductive phase. Research suggests the drop can be as much as 0.3 MJME/kgDM per week of closure1. Harvest pasture silage no later than 35 to 40 days after the last grazing or when a maximum of 10% of the ryegrass seed heads have emerged.
2. Wilt to at least 28% drymatter.
Wilting concentrates the plant sugars and reduces the risk of nutrients being lost from the silage stack as leachate. Silage leachate is surplus water from silage which carries soluble sugars, proteins and nutrients with it as it seeps out of the stack. Silage leachate is one of the most potentially contaminating wastes generated on a farm. It is considered to be 200 times stronger than raw domestic sewage and 40 times stronger than dairy shed waste2.
3. Make sure no dirt is harvested.
Dirt reduces the feed value of silage because it dilutes nutrients and it also carries Clostridial bacteria which produce a butyric fermentation (smells like vomit), ammonia development and an elevated pH. Keep dirt out of the silage by making sure the cutter bar does not skim the ground, harvesting when the weather conditions are dry, and ensuring the stack tractor does not carry dirt into the stack on its tyres.
4. For pit silage, chop to 5 - 7 cm.
Chopping allows for good consolidation, reducing storage and feed-out losses. It also releases plant sugars which are converted to acid by the anaerobic (oxygen-hating) bacteria. This acid drops the silage pH.
5. Add a quality silage inoculant at harvest time.
Quality silage inoculants contain the right strains of lactic acid-producing bacteria to ensure a good fermentation. Just as the acid in vinegar preserves the goodness in food when pickling, so too do the acids in silage fermentation.
All silage loses nutrients over time and the key to reducing these losses is to get the pH of the silage to acidic levels as quickly as possible. This acidity safeguards against a drop in quality and reduces both silage shrinkage and run-off.
The net result is more feed and greater milk production for every tonne of silage harvested - a return of $2.57 for every dollar invested3.
*Milk production per tonne of pasture silage fed is based on three independent dairy trials. Assumes a milksolids payout of $4.25/kg MS.
6. Compact and seal properly.
For stacked silage, spread the material into 100 - 150 mm layers and compact until the surface is firm. Use a high-quality plastic cover and weigh it down with tyres that are touching. Seal the edges with sand or lime. For baled silage, use high-quality wrap and apply it according to the manufacturer's recommendations (i.e. use the recommended stretch factor and number of wraps).
7. Apply good storage management.
Ideally bales should be wrapped close to where they will be stored. If you have to move them, do so carefully to avoid damaging the wrap. Fence the stack or bale storage area to keep livestock out. Place rat bait in bait stations around the stored silage. Check the silage on a regular basis and mend any holes that develop in the cover as soon as possible.
1Wren & Mudford. 1996. Making quality silage. Proceedings of the Ruakura Dairy Farmers Conference 49:100-105.
2Tikkisetty et al, 2004. Environmentally friendly silage management. SIDE Conference.
3Return on investment is calculated using a typical 1127 cost and a milksolids payout of $4.25/kg. Drymatter recovery data used in this calculation is based on 16 pasture silage trials conducted at independent European research stations and submitted to the official German silage additive approval scheme. Milk production per tonne of pasture silage fed is based on three independent dairy cow feeding trials. Unless otherwise stated, inoculant performance is compared to an untreated control.