Hay and Silage
IT’S been a great year for grass growth, but a shocker for making satisfactorily wilted silage.
Earlier in the season, some farmers and contractors were able to harvest some silage, but the break in the wet weather was shorter than we would have liked to ensure the forage was harvested in the desirable dry matter ranges.
It is highly likely that much of this silage will have been ensiled wetter than desirable, especially if baled.
It seems that rain will be an ongoing concern possibly making it difficult to successfully harvest high-quality silage without rain damage this year.
Despite poorer quality silage being made, the little silver lining in the cloud is that, provided paddocks are not chopped up during harvest and pasture is only about half way up the gumboot at cutting, the paddocks will recover well and quickly and soil moisture will allow a longer season in many areas.
Longer pastures will be much slower to recover and be much less dense.
What can be done to minimise the deleterious effects of wet weather on silage quality?
The aim is to harvest chopped stack silage in at about 30 to 35 per cent dry matter (DM) content versus 40 to 50 per cent DM for round baled silage.
Precision chopped silage could be ensiled up to about 40 per cent DM due to the shorter chop length enabling better compaction.
If DM contents are below these targets, the silage will undergo a less desirable fermentation resulting in increased DM losses, be of lower quality and be less palatable to cattle.
This year some very early bales have been much wetter than desired, but by using the latest balers, they are producing very tight bales, with silage additives having been used.
The lack of air, plus additive inclusion has ensured success in most occasions in the past few years.
Don’t count on this if loose bales are produced.
Be aware that even traditional 1.2 metre x 1.2 metre bales will be very heavy (650kg and above).
Delaying cutting too long will also result in silage of low nutritive value, even if undamaged by rain.
These crops will be heavier and unless we get good breaks of quite warm weather to achieve the desired wilting for either stacks or bales, the silage will probably undergo a poorer fermentation if made too wet and/or soil is included in the forage.
Cutting earlier with some rain damage will still result in silage of better quality than that cut later, assuming most paddock damage is avoidable.
Digestibility is dropping about three to five percentage units per seven to 10 days by mid-October and protein content dropping about one to three units, depending on the maturity date of the ryegrass species in the pasture.
The longer a mown crop is on the ground, and/or the more rain that falls on it, the greater the dry matter and quality (energy and protein) losses from plant respiration, microbial and bacterial caused losses, leaching losses and some possible leaf shatter.
Rain can also splash undesirable bacteria onto the forage, basically inoculating the material with undesirable bacteria.
Applying a bacterial silage inoculant is often said to speed up the fermentation of any remaining sugar and result in a good fermentation.
This may apply where the crop has not been exposed to many days of wet weather or wilting has occurred over less than three to four days.
There should be enough plant sugars for the bacteria to convert to a sweet-smelling lactic acid to preserve the forage.
However, there are other products on the market which can handle material exposed to constant drizzle or heavy rain or where wilting has been extended for many days.
These are buffered acid salts, and another contains an enzyme base + sulphur compound which scavenges the oxygen.
You can ask about others suited for over-wet material or extended wilting.
These are the products worth considering this difficult season.
Three final words on silage additives.
1. They will return you at least three to five dollars for every dollar spent.
2. You will not always see the difference between treated and untreated silage although, this year, you may smell the difference.
3. I would recommend using the relevant silage additive in all scenarios.
HARD HARVEST: Pasture and fodder specialist, Frank Mickan said it is highly likely that this year’s silage will be wetter than in an ideal season.