Conserving Grass as Silage or Hay
- Pattern of Grass Growth
When there is not enough grass supplement it with concentrates and silage.
When there is too much grass conserve the extra for feeding in the winter
- Scientific Principle involved in Conserving Grass
The general principle in conserving grass is to stop or slow down the activity of the bacteria that spoil or rot the grass.
Silage:
–Controlled fermentation - reduce the pH to a level that the bacteria cannot work at.
Hay:
–Dehydration - dry the grass out so much that the bacteria cannot work. - Heading Out and Ensiling
Heading out: This is when half of the grass plants have produced seed heads.
Ensiling: This is the process of storing grass or another crop in a silo, clamp or pit for preservation as silage. - When do we Cut?
Silage
–Cut in May when the grass is leafy and highly digestible stage.
–Ensures a good quality winter feed.
Hay
–Cannot cut in May as the weather is not good enough to dry the grass out.
–Cut in June so quality is not as good as silage. - Silage Making
Pile grass up and remove the air by rolling it.
Anaerobic bacteria begin to ferment the silage - turn the carbohydrates into acids which lowers the pH and preserves the grass.
Good Silage
–High level of soluble carbohydrates (sugars and starch)
–Anaerobic bacteria (Streptococcus & Lactobacillus)
–Lactic acid
Bad Silage
–Low levels of carbohydrates
–Clostridium
–Butyric acid - High Carbohydrate Levels
Do not cut when wet.
Allow crop to wilt (dry out in field).
Use double-chop or precision-chop harvesting equipment.
Add molasses (carbohydrate rich) on very lush grass. - Cutting Date
Ensure high Dry Matter Digestibility (DMD)
Half of plants have seed heads showing ( 25th May).
Every day after this there is a reduction in DMD - Seven Steps to Good Silage
1.Cut grass up into small pieces.
2.Transport to clean pit.
3.Apply an additive.
4.Remove clumps of grass to lessen risk of air pockets.
5.Roll grass repeatedly to remove air.
6.Cover with two sheets of heavy-gauge polythene sheeting and place FYM, tyres etc on top to seal pit.
7.Tighten up sides of sheeting at regular intervals as pit subsides to ensure no air enters. - Additives in Silage Production
Acids: Lower the pH of silage inhibiting fermentation process and inhibiting bacterial activity.
Molasses: Increases carbohydrate concentration in the pit, providing extra sugar for fermentation process.
Bacterial inoculants: Speed up fermentation process and reduce pH within the pit.
Enzymes: Break down grass fibres. This provides additional carbohydrate in the form of sugar for fermentation - Additives
Used when the carbohydrate level of the grass is low.
Some farmers always use them for safety.
Two types:
–Stimulants
–Inhibitors - Additives
Stimulants
Source of carbohydrate
Molasses
Applied to grass in the pit in layers (10 l/tonne)
Inhibitors
Source of acid to lower pH
Sulphuric or propionic
Applied during cutting of grass (3-5 l/tonne)
Storing Silage
Usually stored in a pit or clamp.
Must ensure that the effluent can be collected safely.
Other option is big round-bale silage where the grass is cut, wilted, made into bales and wrapped with plastic to make them air tight.
Bales are more expensive but are more convenient especially if only a small amount of silage is being made.
- Round Bales
Advantages:
Quality can be as good as pit silage
Ideal for surplus grass – small amounts can be made
Excess bales can be sold
Cheaper for small farmer where pit cannot be justified
No need for effluent storage facilities
Disadvantages:
High unit costs
Prone to damage if not handled properly
Plastic waste disposal costs - Silage Effluent
Liquid that seeps from silage after it is stored.
It is acidic and can cause serious pollution so it must be stored carefully.
Usually stored in underground tanks and spread on the land with slurry.
The wetter the silage when it is made the more effluent that there will be.
Wilting silage reduces the amount of effluent produced and increases carbohydrate level of silage. - Good Quality Silage
ph 4
Greater than 20% dry matter
70 – 75% digestible
See table page 254 to see characteristics of good and bad silage. - Haymaking
Close field in mid April and apply fertiliser.
Cut grass as close to June 1 as possible when digestibility is high.
We are trying to dry the grass to 20% moisture so only cut when dry weather is expected.
After cutting shake out the grass with a tedder to fluff it up and allow it to dry out quicker.
Continue to ted the hay 2 to 3 times a day until it is dry enough to be baled. (Be careful not to damage the grass by tedding it too roughly)
Bale the hay and bring it into sheds ASAP. - Haymaking
Rotary mower cuts the grass
and leaves it in rows.
The tedder shakes out the grass
allowing it to dry out fast.
Grass should be tedded twice
and as soon as possible after
cutting.
The baler collects the grass
and makes it into bales which
should be moved into storage
as soon as possible.
