By John Lyne
IN MY consultancy work, when I’ve criticised silage for a variety of reasons, invariably, someone or something is to blame, be it contractors, workers or whoever/whatever.
Many farms invest $100,000 or more into silage, and abdicate all responsibility for its quality. It’s astounding.
I doubt there is any other investment/cost of this magnitude we simply hand to someone else or chance; be it by design or by default.
There are a number of critical control points that well managed, can produce quality silage capable of good conversion to milk dollars from both the nutrient perspective and reduced wastage: wastage being the highest cost to silage. These management points can be controlled irrespective of whether we do the silage ourselves, use contractors or employees.
Checking moisture is paramount to good fermentation. Sixty-five per cent moisture is a very well researched optimum for pasture silage (in the low 30s for maize when processed through a chopper).
The real need here is to understand just how quickly cut pasture can dry. I suggest taking a sample straight out of the mower and drying it in a microwave oven to establish its moisture content.
Repeat this each hour by taking another sample from the same windrow. Once we’ve grasped how quickly grass can dry, we are then well placed to schedule baling/ensiling.
When cut pasture is exposed to sunlight it will increase in sugars through photosynthesis.
Sunlight will cause plant water to combine with atmospheric carbon dioxide to form sugars and release oxygen to the atmosphere – hence cut pasture moisture drops quite rapidly in sunlight.
The reverse of this happens overnight – reduced sugars and increased moisture.
Further, tedding two hours after the mower will expose more leaf to sunlight drying it faster and increasing energy (sugars). Leaving silage in windrows, as all mowers do, is not drying, but windrow composting! Inside a windrow it will be 100 per cent humidity; no hope of drying. While sitting in windrows it will be burning off highly digestible sugars and starches that should have been converted to milk.
Last spring I wrote an article entitled ‘Silage In A Day’ which drew criticism, however, try the above and see if you can get cut pasture down to 65per cent moisture within a day.
I assure you it can be done, and is done, producing high energy, very palatable silage reducing wastage and converting profitably to milk dollars.
Air, or oxygen, is the greatest enemy of silage. Exclusion of oxygen is critical to rapid fermentation and stable pH. In the case of balers, running the belt pressure in the red will ensure very dense bales.
Add to this, chopping, and the presence of oxygen in a bale at baling will be greatly reduced.
Both my sons and a number of clients practice both these things and produce extremely high quality silage with no shrinkage (a sign of ongoing fermentation/unstable pH). Exclusion of oxygen will also minimise growth of moulds and yeasts (a cause of heating in silage or hay reducing energy and denaturing protein).
On a warm day, bales need to be wrapped within two hours of baling; in cooler weather, no more than four hours. However, as above, due to being able to make silage in a day, choosing a warm sunny day (increasing sugars and rapid drying) to make silage is good management.
Shifting bales to storage area as soon as possible after baling will reduce plastic movement which allows oxygen back into the bale.
The advent of disc mowers has a corresponding and adverse effect of increasing ash (dirt) in silage.
Feed testing laboratories can verify this.
An increase from 9 per cent ash to 11 per cent ash content can reduce milk production by one litre. Ash, or dirt, has negative impacts on rumen digestive bacteria, as well as the risk of introducing harmful bacteria such as clostridia.
Skids are available from machinery dealers to raise the height of the cutter bar. Research has shown for optimum quality (digestibility), lowest ash content and most rapid regrowth, grass should have a cut height of 10cm.
A secondary benefit of raised cutting height is rapid regrowth. A paddock should still be green after cutting. This indicates the plant has not been defoliated and still has leaf left to capture energy from sunlight for rapid regrowth.
A white paddock indicates total defoliation of the plants and requires energy to be drawn from the root system to grow one leaf. This leaf then takes in energy from sunlight, restores what was borrowed from the root system, then begins growing more leaf – a very slow process.
In uneven or pugged paddocks, disc mowers can ‘scalp’ ryegrass plants killing them and reducing plant density.
Adjusting cutter bar height leaving 10cm of stubble will also reduce ash inclusion from tedding and raking.
None of these management issues creates more physical work; mental, certainly, but unless we improve our productivity in both increased dry matter harvest/ha/year, and increase digestibility (conversion of forage dollars to milk dollars), we face further low milk prices from more competitive milk producing nations (USA especially).
My greatest fear for our industry is shrinkage to a domestic supply only industry.
Although this may sound attractive in terms of milk price, it leaves us extremely vulnerable to cheaper imports and total annihilation of our dairy industry, as other local food producers have found.
Our government has only one concern in this regard: cheap food for metropolitan Australia with no concern for where it comes from.
– John Lyne is a dairy production specialist with Dairytech Nutrition www.dairytechnutrition.com.au