Metods to optimise the efficient metabolic conversion of nutrient in feeds to animal products, and thus to reduce the amount of nutrients in livetsock manure
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Most grain is used for feeding, and the normal practice is to conserve it by drying it to less than 14% moisture at harvest and keeping it in open, roofed stores until use.
Another way is to store it in sealed air-tight silos. What happen under such conditions is that the grain quickly converts the oxygen in the silo to carbon dioxide (CO2) and alcohol - i.e. the grain "kills itself". The grain loses its germination ability, and there is no risk of vermins, as they cannot live in oxygen-free surroundings. The process preserves and ferments the grain.
Farmers invest in the sealed grain stores simply to save the drying costs and to avoid risks of spill. This way to store the grain has also a positive impact on the digestibility of the protein and phosphporus in the grain.
Sealed, air-tight silos for grain storage are available in farm-scale as well as industrial scale.
Under air-tight conditions, the grain quickly converts the oxygen in the silo to carbon dioxide (CO2) and alcohol - i.e. the grain "kills itself". The grain loses its germination ability, and there is no risk of vermins, as they cannot live in oxygen-free surroundings. The process preserves and ferments the grain.
Effects on air (emissions):
Effects on water/soil (and management):
Aarhus University has in a pig feeding trial shown that grain from sealed air-tight storage had 3% higher digestibility of the protein, and 12% higher digestibility of the phosphorus due to higher phytase effect. The differences are statistically significant. The trial results are interesting from an environmental perspective, and shows that sealed grain storing has the potential to be a technology that can help closing nutrient cycles in agriculture, because it enable pig production with less input of protein (nitrogen) and phosphorus.
The trial was made as a digestibility and balance trial with 16 slaughter pigs (8 for trial, 8 for control) at about 45 kg’s weight. The pigs were fed the same diet, the only difference being the way the grain, constituting 70.9% of the ration, had been stored. The results of the trial are shown in the following table:
Digestibility trial with slaughter pigs, fed with normal versus air-tight store grain.
(normal stored grain)
(air-tight stored grain)
Dry matter, %
p = 0.10
p < 0.10
Feed units per kg dry matter
While the trial showed significant effects of air-tight storing of grain on the digestibility of protein and phosphorus, it is interesting to see that other observed feed parameters also were affected positively, although not significantly.
The way to store grain does not nourish vermins.