Successful Cereal Silage
Date: 13 November 2015
Whole-crop cereals such as wheat, barley or triticale offer options to produce silage in regions where maize silage is limited by a lack of heat or out of season frosts. NZ research1 has shown that feed quality of cereal silage can be variable. It is important to harvest at the right maturity and employ good silage management practices to get the best value out of cereal silages.
Time of harvest
Whole crop cereals can be harvested at two stages of growth – at the flag leaf/boot stage or at the soft dough stage. 2,3
Flag leaf/boot – early ear emergence stage
The flag leaf is usually the widest leaf in oats, wheat and triticale and is the last leaf to appear before the head emerges. Flag leaves in barley are often the smallest.
Boot is defined as the stage when the developing ear is expanding within the flag leaf sheath. The awn tips and ear will emerge soon after. Harvesting at this stage will ensure the best protein and energy without compromising the yield too much. There is a trade-off between declining quality and higher yield as the stem and ears develop. Overall quality declines from this stage but recovers toward the end of grain fill as the starch content rises.
Soft dough stage
As cereal grains mature they pass through the clear liquid stage, then become milky, followed by the soft and hard dough stages. The ideal time for this later harvest is when the inside of the grain has a texture similar to cheese. Harvesting at this stage will ensure there is sufficient moisture for ensiling and deliver near optimum yield and near optimum energy. At the soft dough stage, protein content will be lower than at the boot stage.
Cereal crops should not be harvested at the clear liquid or early milk stage as the resulting silage often has reduced quality and possibly lower palatability for stock.
Crops must be wilted when harvested at the boot/early ear emergence stage, but they can be directly chopped at the soft dough stage. The recommended harvest drymatter contents for the respective stages are given in Table 1. The window of opportunity for optimum silage making is narrow (often less than 7 days). If the crop is too dry (>46% DM) it may be difficult to compact and can trap more air in the silage leading to spoilage. Alternatively, if it is too wet the silage quality will be poor, with spoilage and possible losses of nutrient as silage run-off (also known as silage effluent). 4
Table 1: Target drymatter content for ensiling cereals5
Flag leaf – Boot stage
Soft dough stage
32 - 40%*
Barley, wheat and triticale
32 - 40%*
36 - 42%
* Some balers may require higher drymatter levels.
Crops that are harvested at the flag leaf/boot stage will have field drymatter levels of 18 - 22% and therefore need to be wilted to promote the best fermentation characteristics.
For best results at flag leaf/boot stage:
- Cut at approximately 7 - 10 cm in height.
- Where possible use a mower conditioner to crimp/crack the stems. This will encourage faster wilting.
- To encourage fast wilting, leave the windrow wide and thin especially if the crop is dense.
Wheat, barley and triticale crops that are at the soft dough stage will be in the desired harvest drymatter range as a standing crop. Climatic conditions approaching harvest time will greatly influence the increase in crop drymatter percentage. Research has shown triticale can increase by approximately 1% drymatter per day and barley by 1.5 - 2.0% per day, however under very hot dry conditions these drying rates will increase substantially and they can be slower in overcast conditions. 6
To maximise silage quality:
- Collect a representative sample and send it to a commercial laboratory to determine drymatter levels.
- Preferably harvest using a precision chop forage harvester.
- Cut at approximately 7 - 10 cm in height.
- If the crop is drier, use a shorter chop length (2 cm) to assist with compaction.
- If the crop is wetter, increase the chop length to 5 cm.
Besides crop maturity and the drymatter % of the crop, an efficient silage fermentation process is critical to achieve good results from cereal silage. Overseas research7 has identified the risk of Clostridia fermentation in cereal silages which can lead to increased losses and bad smelling butyric silage. It is strongly recommended to use a proven inoculant like Pioneer® brand 1174 to dominate the fermentation process and achieve an efficient fermentation and palatable silage. Research shows a four to one return on the cost of applying Pioneer® brand 1174 silage inoculant that minimises the shrinkage of the stack or bales and boosts feed quality. Trials showed that for a range of silages, including oats and wheat, more drymatter was available than in untreated silage for the same tonnage of chopped forage.8 In silage treated with Pioneer® brand 1174 inoculant, the drymatter recovery was 87% in bunkers, stacks and bales compared to less than 85% when ensiled without any inoculant. As well as an increase in drymatter yield the data from six cattle feeding trials showed an increase of 4.4 kg in cattle liveweight for each tonne of Pioneer® brand 1174 inoculated silage compared to cattle fed untreated silage. 9
At later stages of maturity, it will be increasingly challenging to achieve target compaction densities of 200 – 240 kgDM/m3, because hollow stems act like a cushion. Short precision chopping and an immediate covering will improve fermentation conditions. It is also recommended to plan silage stack dimensions to have a silage face small enough to allow feed-out rates of 1.5 - 2.0 m per week.
For more information on cereal silage inoculants, contact your local Pioneer representative.
1Stevens, D.R.; Platfoot, G.J.; Hyslop, M.G.; Knight, T.L.; Corson, I.D. & Littlejohn, R.J. 2004. Dairy cow production when supplemented with whole-crop cereal silages in spring and autumn. Proceedings of the New Zealand Grassland Association 66: 75–82
2de Ruiter, J.M.; Hanson, R. 2004. Whole crop cereal silage – production and use in dairy, beef, sheep and deer farming. New Zealand Institute for Crop & Food Research Limited. ISBN 0-478-10849-4. 33pp.
3When to cut forage cereals. Agnote 1243. Department of Primary Industries, Victoria, Australia.
4de Ruiter, J.M.; Hanson, R. 2004. Whole crop cereal silage – production and use in dairy, beef, sheep and deer farming. New Zealand Institute for Crop & Food Research Limited. ISBN 0-478-10849-4. 33pp.
5Adapted from: Forage Cereals: Harvesting whole-crop cereal silage. Agnote 1244. Department of Primary Industries, Victoria, Australia.
6Forage Cereals: Harvesting whole-crop cereal silage. Agnote 1244. Department of Primary Industries, Victoria, Australia
7 Steinhoefel, O. 2006. Silagen aus Getreideganzpflanzen (Silages from whole plant cereals). Praxishandbuch Futterkonservierung. 7. Auflage 2006, DLG Verlag ISBN 3-7690-0677-1
8Drymatter recovery data are based on 10 trials conducted with a range of silages including oats, wheat, lucerne, forage sorghum and maize.
9Beef production per tonne of silage fed is based on six beef feeding trials conducted using oats, wheat, lucerne, forage sorghum and maize. Assumes a beef price of $5.50/kg carcass and a dressing out percentage of 50%.