Making and feeding high quality silage with lower fibre levels encourages higher feed intakes and better cow performance. This article highlights five easy steps for making high-quality, temperate pasture silage.
1 Cutting pastures early
Cut early in the season. For maximum silage quality, cut pastures when they are at or near canopy closure.
This is also the optimum stage of growth for grazing in spring.
Providing pasture is at or only slightly past grazing height, and harvested in good weather conditions, milk production will be only marginally less than if the same pasture had been grazed by the cows.
Wilting rate of the mown pasture has a big impact on silage quality. The time of day that pasture is cut impacts on the wilting rate.
The following should be considered when deciding on mowing time to aid rapid drying but to avoid overdrying:
- Mow after dew has lifted.
- Match mowing and harvesting operations so that mown material is not left unharvested for lengthy periods.
- Reduce wilting periods for forages, such as legumes and young, leafy plants.
- Delay mowing until mid to late afternoon to reduce the risk of overdrying the forage during hot, dry and windy weather.
- Stagger mowing and narrow the swath width if there is a real risk of over-drying.
2 Wilt and harvest quickly
Have the forage in the pit or bale within 24-48 hours, if possible.
Wilt rapidly to the target dry matter (baled silage 40-50 per cent and pit silage 32-38pc) to reduce potential dry matter and quality losses.
Several strategies that can increase wilting rates:
- Mow crops at canopy closure (lighter crops with more leaf and less stem).
- Use a mower-conditioner with flail or tynes.
- Follow the mower with a tedder to spread the forage. Ted within 0.5-2 hours after mowing while plant stomata are still open, if possible, to substantially increase rate of wilting.
- Leave the swath of the conditioned forage as wide as possible (moisture evaporates quicker from thin, wide swaths).
- Do not over wilt field losses increase and silage is harder to compact.
- Additives are available to improve fermentation if wilting conditions are poor.
- Inoculants may also improve silage quality and animal production.
3 Compacting stacks and bales
Compact stacks and make bales as dense as possible.
The better the compaction, the less air will be trapped in the stack or bale resulting in a higher quality silage
For bulk stacks:
- Chop material short (10-30 millimetres).
- Spread the forage thinly (150mm) to ensure thorough compaction.
- Roll slowly to allow the tractor weight to compact the forage.
For baled silage:
- Set bale density as dense as possible on the baler.
- Slower baling will increase bale density.
- Chopping balers (knives) can increase density by 8-15pc.
- Ensure feedout equipment can handle shorter chopped bale silage.
4 Sealing airtight
Seal airtight as soon as possible after harvesting.
Seal stacks, don't just cover them.
Finish rolling immediately after harvest is completed. Avoid rolling the next morning as this just 'pumps' more oxygen into the stack.
Rolling should keep up with forage delivery from the paddock.
Seal pits or stacks as soon as harvest is complete. If leaving overnight minimise air getting into the stack by placing plastic on the stack and weighing down the edges. Finish weighing down the stack next morning and ensure seals are airtight.
For an airtight seal use gravel bags, filled with pea gravel or washed sand along bunker walls and stack surface. Even a double row of tyres around the perimeter does not achieve an airtight seal.
Apply at least four layers of film to individually stretch wrapped bales.
Apply six layers: if placing on stiff stubble, e.g. cereal; for stalky crops e.g. lucerne; if transporting; if wishing to store for up to two years.
Apply at least six layers on continuous in-line wrapped bales.
Minimise damage to stretch wrap by wrapping at the storage site or use specialist equipment to transport bales to storage.
If a white/grey mould is present in silage, air has been or is present and should be prevented in future.
5 Maintaining quality
Maintain silage quality by repairing holes as soon as possible.
Ensure the area to be patched is clean and dry.
Use specific silage repair tape of similar colour to the holed plastic. This minimises the difference in contracting and expanding in hot/cool conditions and stops the seal leaking.
Cut tape to length before applying.
Article courtesy of Gardiner Dairy Foundation and Dairy Australia Quality Pasture Silage booklet, developed in 2016 in response to the milk price drop. Portions of this booklet have been adapted from the TopFodder Successful Silage manual.
