The substance flow balance of the new Fertiliser Regulation forces agricultural enterprises to set the phosphorus content of the feed accurately. The rations must meet the phosphorus needs of the animals, while minimising the phosphorus content of the animal faeces. Consequently, there is little room for variation in the phosphorus content. Different crude fibre sources can add different amounts of additional phosphorus to the ration. Lignocellulose, which is low in phosphorus, is especially suitable for use as a crude fibre component for a phosphorus-reduced feeding strategy.
The new Fertiliser Regulation bears a big challenge for agricultural enterprises: the control values for the operational nutrient surplus will be gradually reduced in the next few years. Thus the limit values for nitrogen and phosphorus input into agricultural land will decrease. To be able to adhere to the limit values, agricultural enterprises must accurately monitor animal faeces.
The phosphorus demand of livestock is well researched, and supply recommendations exist for many types of animals and their production phases. Today, it is not the undersupply of animals with phosphorus that poses a challenge for agricultural operations, but oversupply. Depending on the components, the overall phosphorus content of many feeds often exceeds the animals’ needs. The excess phosphorus, which the animal organism cannot absorb, is excreted undigested and negatively affects the substance flow balance of the operation.
To cover the animal’s phosphorus demand and at the same time minimise the phosphorus content of animal faeces, the following is necessary:
- The animal demand must be determined
- The P content of the feed must be taken into account
- The nutrients in the ration must be adjusted to achieve the necessary content; any surplus is deliberately foregone
- The digestibility of the nutrients in the ration is considered
- Feeding is adjusted to the need in the phases (e.g. rearing feed, fattening feed or finishing feed for broilers)
Phosphorus-reduced feeding strategies for cattle, pigs and poultry
As regards compound feed for cattle, pigs and poultry, phosphorus is added to the ration above all by vegetal crude fibre components. Most compound feeds contain sufficient phosphorus – both free phosphorus and phytate-bound phosphorus. Phytases also make available the phytate-bound phosphorus so that the animal organism can use it. If required, phytases are added to compound feed. Phytases in the feed – both plant-intrinsic and added – and microbial phytases found in the digestive system of the animals improve the digestibility of phosphorus.
To make sure that the limit values for phosphorus input into agricultural land are not exceeded, a phosphorus-reduced feeding strategy is necessary. This enables the phosphorus need of the animal organism to be met, while reducing the content of phosphorus in the animal faeces to a minimum. A comparison of the phosphorus content of different crude fibre sources is required for this. Crude fibre components with a high phosphorus content increase the overall phosphorus content of the rations and often the amount of phosphorus in the animal faeces. The phosphorus content in some typical crude fibre sources is very high and can vary depending on the time of year, weather and cultivation region. Regular bulk elemental analysis of the feed is essential to avoid putting a further strain on the substance flow balance.
The natural lignocellulose JELUVET® has an extremely low content of phosphorus. The overall phosphorus content – both free phosphorus and phytate-bound phosphorus – is below the detection limit of 0.1 g/kg original substance (own analyses, method according to EN 16943). Lignocellulose therefore does not add additional phosphorus to the ration when used as a crude fibre component. Lignocellulose helps you to reliably adjust the crude fibre content of compound feed without adding further phosphorus to the ration. Low-phosphorus lignocellulose is therefore especially suitable as a crude fibre component for a phosphorus-reduced feeding strategy.
Phosphorus content of some crude fibre sources
Comparison values of the phosphorus content in some crude fibre sources (all values, except P value of lignocellulose, from Gruber feeding value table)
|Crude fibre source||Dry matter in g/kg os||Crude fibre in g/kg os||Phosphorus in g/kg os|
|Grass meal (red clover)||900||203,0||2.7|
|Maize grain silage||650||25||3.5|
|Meadow rich in grass (silage)||350||78||1.5|