On a farm visit last year just after first cut, John Williams, Micron Regional Sales Manager made an unwanted discovery. “I took the opportunity to inspect the cut grass and from the field gateway it all looked good, ready to be rowed and picked up in the morning. I wanted to check the cutting height which would influence drying times and regrowth."
As you can see, nice and green underneath which will recover quickly and allow the farmer to take another cut in 4 – 5 weeks. This also indicates very good ‘d’ value which will provide good protein and energy values. dNDF will also be very good, but then I took a closer look. I could clearly see that there was slurry residue left over from application some 5 weeks ago using a dripple bar. With a period of dry weather leading up to silaging, there had not been enough rain to soak the slurry into the soil.
The crop from the field, now in the silage pit, is therefore likely to be heavily contaminated with Bacillus, Clostridium, Escherichia and all sorts of other spoilage organisms.
Slurry that hasn’t been well washed in will end up in the clamp and not at the grass roots where it should be, presenting considerable risk of an unstable clamp face at opening, even if a good fermentation is achieved.
Rain would have avoided this problem, but we all know it is often impossible it is to get the right type of rain at the right time!
In this case the farmer was informed of my findings and recommended to harvest these contaminated fields first, so that the crop can be ensiled at the bottom of the clamp where consolidation will be greatest and lactic acid generation from above will soak down. Lower levels of the clamp (high sugar,<30% DM>) tend to have decreased pH. Hopefully this should control any mould growth later.
Tip! Take a closer look at the grass before mowing, look for any slurry residue or mould before you mow, so that you can adjust your cutting plans accordingly.
Tip! Use a slurry additive like MicroZyme R next season to stored slurry, as this will help reduce solids whilst improving the valuable nitrogen retention, making the slurry easier to manage, whilst optimising it as a fertiliser.
What else may be hidden in the sward? What about mould?
Lots of microscopic organisms have a reproductive phase that have white, fluffy looking spore heads. This includes moulds but also many species of Bacillus
bacteria. Generally mould or Bacillus spp
. of bacteria are not harmful to livestock, unless it is Listeria
, which is very harmful. However, while the organisms are growing they will be using the sugars and proteins in the plant material and making less available to livestock.
Any moulds present at the time of ensiling will still be present post ensiling, as it is impossible to rid all of these organisms in the ensiling process.
Mould may also be present in the field in spore form and won’t grow actively until it gets into the right environmental conditions, and fields that are near damp areas or commonly grow mushrooms will have a higher risk of fungal/mould contamination.
So, during mowing there is a very high risk of introducing the fungal spores into the silage, lowering the quality and stability of the forage, and increasing the risk of spoilage and wasted silage when opening the clamp. Furthermore, if the mould present on the crop come under stress (e.g. when exposed to oxygen when the clamp is opened), the risk of mycotoxins being present in the feed increases.
Before you mow, take a look within the sward to check for possible contamination issues, that could be taken into the crop at mowing.