With May rainfall levels twice the norm in places Teagasc have in recent days sent out notes  to advisers yesterday on making silage in difficult conditions. 

Key steps:

1. Silage digestibility is deteriorating by 2.5-3.0% units per week at this stage but lodged crops, lying under wet conditions, can deteriorate by up to 7-9% units in a week.

2. Check sugar content of grass with your local adviser.

  • Ideally, sugar content should be above 3% for good preservation.
  • If sugars are below 2%, you will need to either wilt the crop or use an additive. If using an additive it needs to be a source of sugar or an acid to aid preservation. Inoculants are not recommended to aid preservation in difficult conditions.
  • If sugars are 2-3%, the situation is less clearcut. Many crops are headed out at this stage and should preserve adequately in most cases, provided pits are filled and sealed quickly. Any level of wilting will help these crops. If there is still any concern, i.e. crops that are still very lush, then its best to recommend a sugar based or acid based additive.

3. Only mow grass once certain that you can finish the job within 24 hours of starting. Watch the weather forecast carefully, if there is a 24-36 hour window of good weather in the next few days, delay harvesting until then but don’t delay indefinitely. Mown crops will deteriorate quickly unless they are drying. If these crops are not drying, pick these crops up.

4. Any degree of drying will help. Only ted a crop out, if the forecast is for reasonable drying. Even a 12 hour wilt will help dry the crop. If weather conditions improve and a crop can be wilted, preservation should be relatively straightforward. Thus, if feasible, this must be an objective. These crops will need to be excellently sealed to ensure they are stored under genuinely air-free conditions. Otherwise there is a risk of mould growth.

5. Avoid soil contamination.

6. Minimise soil compaction damage.

7. Fill, roll and seal well and do this quickly.

8. Effluent will be an issue with wet silages—ensure a good drainage system to get the effluent away quickly. There is feeding value in effluent ~ 17 litres = 1 kg of barley. Some may decide to use an absorbant to reduce effluent loss. Soya hulls, beet pulp and citrus pulp work well. This can be costly.

If grass sugar concentrations are genuinely very low and harvesting cannot be deferred any longer, the even and adequate application of acid (2.5 to 3.5 litres/tonne wet grass) or sugar (10 to 20 litres molasses or 50+kg molassed beet pulp or citrus pulp per tonne wet grass) -based additives are the most reliable ways to aid preservation. Fresh yields of wet grass will be very high on many farms, and yields in excess of 40 tonnes per hectare will not be uncommon. Application rates of additives will need to take such potentially high yields into account