Industry Partners

Prairie Swine Centre is an affiliate of the University of Saskatchewan

Prairie Swine Centre is grateful for the assistance of the George Morris Centre in developing the economics portion of Pork Insight.

Financial support for the Enterprise Model Project and Pork Insight has been provided by:

Author(s): Duxbury-Berg, L.
Publication Date: January 1, 1997
Reference: National Hog Farmer - September 15, 1997. pp 32, 34, 36, 38
Country: United States


Growing pig need phosphorus to grow, to have a good feed conversion, to produce a lean carcass and also to have strong bones (bones with a good mineral level). The phosphorus contained in the feedgrains is poorly used by the digestive track of the growing pigs because an important portion of it is bound in the form of phytate: 66% of the phosphorus in the corn and 61% in the soybean. So the feed industry supplement the pig’s diet using inorganic phosphorus sources (monocalcium phosphate, dicalcium phosphate and deflourinated phosphate. The supplemented diet gives the pig the phosphorus it needs and the unavailable or unusable phosphorus (phytate) gets release in the manure produced by the animal. The problem with the excess phosphorus in the manure is that when fertilization is done according to the plant’s nitrogen needs, the volume applied contains more phosphorus than the plant needs. The excess phosphorus is relatively immobile and is absorbed onto soil particles.
Microbial phytase, an enzyme produce by the Aspergillus niger, can be added to the diet of the pigs to make the phytate phosphorus contained in the grains available. Experiments have shown significant reduction in the phosphorus excretion with pigs fed low phosphorus diets containing phytase (of 20 to 40% at the University of Kentucky and in the Netherlands where phytase is used in 60% of the swine rations, the phosphorus contain has decreased from .73 g/lb. of manure in 1973 to .30g/lb of manure in 1995) .
A specialist for the Netherlands, Age Jongbloed, mention that so far the nutritional approach has been the one leading to the most significant reduction in pollution and is the most cost efficient.
The microbial form of phytase from BASF company (Bart Cousins, Fort Dodge, IA) costs $1.36/lb and 0.8lb/ton should be added to complete feed providing 136 phytase units/lb.
Phytase added to the feed should be well mixed and as it is an enzyme no heating process should be done after incorporated. A liquid form can be sprayed on the pellets.

As mentioned, the phosphorus in excess will be stored in the soil. At a high concentration, the phosphorus will leach to the surface water. Thus it is important to prevent phosphorus from being excessively stored in the soil. Phytase is a good and effective way of doing it because the feed is used more efficiently by the pigs and less phosphorus is excreted in the manure.

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