Whole crop silage heating stems from rapid summer senescence
Livestock farmers who made whole crop silage this summer are being urged to pay careful attention to clamp faces once opened. Excessive heating problems are being reported in a number of areas, especially in the unusually high dry matter crops ensiled this year, and the situation has been exacerbated by the continuing warm ambient temperatures.
Clamps should be checked up to half a metre behind the face, where the microbes (including moulds) responsible for aerobic spoilage create heat when using up valuable nutrients in the silage. The same process forms the initial stage in composting, and the resulting moulds can produce damaging mycotoxins, which at best will reduce palatability, but can potentially cause digestive upsets, reduce production and negatively influence fertility.
"In some cases, clamp faces are heating up overnight, leading to high levels of aerobic spoilage and moulds," explains KW Alternative Feeds nutritionist Dave Collett. "If heating is taking place, make sure all mouldy material is discarded and speak to your nutritionist to see if it's possible increase the inclusion of whole crop in the ration to work across the face faster.
"Mixed rations will also tend to deteriorate faster, so include a mould inhibitor such as Regulator Feed-Out in the ration to reduce the rate of aerobic activity, clean feed troughs of waste more regularly and consider whether it's practical to increase the number of times fresh feed is offered."
Regulator Feed-Out is a granular, sulphur-based additive applied at a rate of 0.5 1.0kg/tonne FW of silage or ration (depending on the severity of the instability problem) that reduces heating, surface spoilage and nutrient loss in silages and mixed rations. Independent research using Regulator Feed-Out has shown up to a three-fold increase in feed stability (time to onset of heating, Teagsasc), along with improvements in both dry matter intakes (5%/cow/day, University of Reading) and animal performance (+4% milk yield, +3% milk protein, CEDAR).
"Much of the problem stems from the extremely fast rate at which cereal crops ripened and senesced under the high summer temperatures," continues Mr Collett. "Grains moved through the various stages of ripening so rapidly that a number of farms missed the opportunity to harvest for silage this year, and it would appear that although crops were clamped at the 'ideal' grain stage, plant DM was much higher than normal.
"Once a clamp is full with excessively dry material, there's very little that can be done to actually 'stop' the problem. For most farms, it's a case of managing the situation to minimise the impact on animal health and performance."
