Introduction
Aerobic spoilage can result in significant losses, which increase with time of exposure to air. DM losses can exceed 30% and quality losses can be significant.
Not only is silage intake often depressed, animals may reject hot, spoiled silage. The importance of air penetration and rate of feed-out for silages of varying aerobic stability is highlighted in Figure 2.10. Air penetration is greater in poorly compacted silages and where there is greater disturbance of the silage face.
The results shown in Figure 2.10 demonstrate that a reduction in air penetration and an increase in feedout rate can significantly reduce temperature rise, particularly with unstable silage.
The time between when the silage is first exposed to air and when spoilage commences at the exposed face varies from a few hours to several days. A large number of factors can reduce the susceptibility of a silage to aerobic spoilage.
The key management factors are:
- Rapid wilt, harvest and seal without delay;
- Good compaction (low silage porosity) to reduce the air available for the aerobic organisms responsible for spoilage, and to minimise air penetration into the exposed face during feeding;
- Sufficiently rapid feedout to minimise the time of exposure to air; and
- Minimum disturbance of the silage face during feedout to reduce the rate of air penetration.
US: Unstable – stable for only 1 day. MS: Moderate – stable for 3 days. S: Stable – stable for 7 days.
