Optimizing Silage Production in a Drought Season
“Irrespective of quantities of rainfall, the quantity of silage we have to feed will be affected by decisions made on all our farms,” says Dr David Davies, director at specialist consultancy Silage Solutions and advisor to the Silage Advisory Centre.
Quality not Yield is Critical
According to Dr Davies the first major decision is when and how to cut.
“When yields are low, it is tempting to put off mowing by a week or two to increase yield. In many situations this is false economy.
“Once grass matures and seed head formation is initiated, the feed value to ruminants is significantly reduced, resulting in the need, next winter, for greater quantities of expensive purchased concentrates.
“Whilst it is accepted that yield of silage from that particular cut will increase the recovery time of grass after a delayed grass cut has been taken is longer and so annual yield of forage is likely to be reduced.”
The second appealing decision is to lower the cutting height to increase yield. Dr Davies believes that again this is false economy.
“Reducing cutting height will increase soil contamination and thus lead to a poorer fermentation with higher levels of DM losses occurring during the storage period, so reducing the quantity of silage in the pit not increasing it.
“In addition, grass fields that have been ‘scalped’ have longer recovery times than ones cut at the minimum recommended stubble height of 2.5 inches. So if you do get that much needed shower of rain after cutting the grass won’t be ready to make the best use of it.”
Reducing Field and Storage Losses
When it comes to picking the forage up it is essential to ensure the forage ‘ends-up’ in the silage pit.
“Prolonged dry spells mean that the grass at cutting has a higher DM than usual, which means once cut the crop dries quicker than you may be expecting. So aim for a maximum of 35% DM for silage going into your clamp and ensure that the forage harvester is set to reduce in field losses, even if it means putting less in each trailer and doing more carting.
Alternatively, Dr Davies recommends considering using bales where the field losses of forage are much less than those put through a forage harvester.
“Baled silage can considerably lower losses during production and storage compared to clamp silage. Scientific studies show that bale DM losses range from less than 5% to 15% whereas DM losses associated with silage in clamps range between 20% and 40%.”
Further losses of DM during the silage storage phase can be avoided by using a good inoculant containing homofermentative lactic acid bacteria to control the fermentation and reduce the production of wasteful end-products.
Strategic Use of Bales
Finally, Dr. Davies recommends the strategic use of bales to help minimise aerobic spoilage losses.
“If it is looking like grazed forage is going to be short this summer and that buffer feeding will be required, then rather than running the risk of losing more silage to aerobic spoilage problems when you open the pit in the heat of the summer months to feed what is likely to relatively small quantities of silage, consider making some bales to cover this short fall and leave the silage clamp shut until you will be able to manage it properly to ensure you minimise aerobic spoilage losses.”