Silage has been used as a roughage source for ruminant animals for many years. The most common silage crops are maize and oats, but lucerne and sorghum can also be ensiled with great success, writes Wikkie van Schoor, Dairy Technical Advisor at Meadow Feeds.
Silage-making needs to be properly planned and fluently executed to achieve the best results with the available plant material. It is important to pay attention to a few basic principles regarding the ensiling process to get maximum value out of the plant material.
In silage-making, the two most important rules are:
- The correct moisture content must be present at cutting and entry into the bunker to ensure optimum conditions for the micro-organisms required to drive the anaerobic fermentation process;
- Maximum compaction must be achieved to expel as much oxygen as possible.
In this difficult time of high production costs, there are management opportunities to lower feed costs and produce more and better silage. Remember, the more quality silage available, the less concentration is required.
A complete ration is often balanced according to the quantity and quality of ingredients available on the farm. Maize and oat silage often form the basis of the total mixed ration of dairy cows. It is a proven method of retaining nutrients and storing feed if ensiled properly.
ALSO READ: Guidelines for successful heifer rearing
Importance of proper preparation
The most common methods of ensiling are by digging a pit or trench in the ground or making a heap on a slightly sloped piece of ground. A slope is important as it allows water to drain away from the material.
The equipment should be serviced before the ensiling process starts. The blades on the cutting equipment must be in good shape. Always keep spare parts readily available in case of emergency. Plan and prepare for the unexpected.
Perform routine checks on the blades to ensure the ideal cut length and proper compaction. Any delays during ensiling will negatively impact the silage quality. Plastic sheeting and old discarded tyres are used for covering the silage to prevent the penetration of oxygen and water.
What to avoid
Interruptions during the cutting and compaction stages will disrupt the required anaerobic fermentation by allowing extended exposure to oxygen that may result in the growth of undesirable moulds and fungi that could limit feed intake. It may not always look that bad, but pockets of mould can develop and no inoculant can fix that.
Poorly prepared silage has an increased risk for mycotoxin contamination that will impair animal performance. This will lead to extra costs for toxin binders and veterinary services to rectify the problem. Reduced animal performance can be expected even if the problem was fixed.
It is important to cut the plant material at the right moisture level. The ideal dry matter content range for ensiling is 30% to 40%. Plant material is still too wet under 30% and compaction becomes difficult above 40%.
The process
Proper preparation is essential to ensure a smooth process without delays so that the silage can be made in the shortest possible time. There must be enough receiver wagons to stay ahead of the cutting machine, but if the wagons arrive too quickly on-site good compaction will be difficult to achieve.
The material must be spread evenly in thin layers and continuously compacted by driving tractors and other heavy machinery over it. At this stage, silage inoculants or molasses syrup can also be added to the plant material to further improve the process.
Single-wheeled tractors with extra weight or water in their tyres work well for compaction. Give special attention to the sides of the heap to achieve even compaction throughout the heap. When the last silage is delivered, it is advisable to keep compacting the heap for another 12 hours.
Good compaction basics
Good compaction is typically achieved when the tractor wheels do not sink into the plant material anymore, but run on top of it. The extra fuel used through additional compaction will not be wasted and better silage will prove the point. Proper compaction expels most of the oxygen trapped between the plant material and in this way assists anaerobic fermentation to achieve a rapid decrease in pH required for the preservation of the silage.
Cover the heap or bunker with plastic sheets immediately after completing the compaction process. It is important to ensure that the plastic covers the complete surface area to prevent oxygen or water to enter. For the same reason, the plastic sheeting must be rolled where different sheets join each other to ensure an air-tight seal. Old tyres or sand are used to keep the plastic sheets down and prevent oxygen penetration.
The heat from the fermentation process will initially increase the temperature of the silage. However, as soon as the pH has decreased sufficiently, the process has stabilised and proper preservation has been achieved, and the silage will cool down.
Prevent damage to the plastic sheets that can result in water and/or oxygen entering the silage, which will cause secondary fermentation and damage to occur.
Standing the test of time
It is important to manage the face of the silage bunker to limit oxygen penetration once it has been opened. Well-prepared silage will stay well preserved for a long time and provide excellent nutrition to all ruminants during the dry season.
A little attention to detail will ensure the best quality. Remember: making bad silage is an expensive exercise and good silage is nutritious and cheap fodder!
Enjoyed reading? Tell us why with a quick 5-min survey
Sign up for Farmer’s Inside Track: Join our exclusive platform for new entrants into farming and agri-business, with newsletters and podcasts.
