How important is adding phosphate to the diets of pigs? Do they not get some of this out of the soil if free range? If free range then the farmer may have applied it at each cropping period and surely there is possibility that a build up of phosphate might be available to the pig. If given to the pig in their diets how long does it take to build up in the soil and what are the effects on the environment or can the pigs use this phosphate in the ground?
Dear Noni, it is a good observation, and I don´t have a clear answer but a reflection. You are right, fertilizers include phosphate in them, but generally speaking these become soluble in the soil and are taken up by crops, plants. Manure, considered as a fertilizer, therefore supplies with P to the soil as well; but the normal fate of this P, which can be in inorganic and organic form, would be that it is absorbed by plants and converted into a P which is organic, linked to the phytic acid molecule in the form of phytate-P. So, pigs in free range, indeed will take P by eating roots, grass, plants, but in my opinion - not an expert in this matter- it would be for them difficult to use since they have almost no phytase (some produced by microflora even by the gut itself, but not relevant). Hope it helps. Rafa from Spain. Congratulations to the Aussies, doing well at the Olympics, though today we beat you in water-polo. :-)
Hello Noni again. Olympics as usual......China, US, UK....and not much for others, well..... Your comment is fair and I will answer to the best of my knowledge. Indeed pigs do not have phytase - or the one they have, or is produced by micorbes is not too active/effective vs the P-phytate -; but pigs still need P for growth, normal metabolism (energy in ATP contains P), in a word they need it to live. What we are normally doing when feeding complete feed is to formulate with a min of digP (avP in some countries/areas); at the same time we use a feed with eg: 0,35% digP, we also provide a totalP of about 0,75%. This means 0,40% will not be used by the pig but excreted (this is the so called P-phytate). This 0,35% basically is provided by inorganic P we add into the diet in the form of MCP/DCP, the rest, 0,40% comes from the P supplied with the rest of vegetable ingredients (grains, soya bean meal, rapeseed meal,...), which as said, will not be used. So, what are we seeking with a phytase?; very simple - and difficult at the same time - , we help the pig to release P from that 040% of P-phytate. By doing so, we reduce the P excreted to the environment but at the same time we can work the formulation out again, setting a new and lower initial level of digP (lower then 0,35%) because we know more P from the total non digestible P will eventually be used by the pig. Reaching this point Noni I hope I helped more than a mixed up your ideas. From now on, have a nice day........tomorrow I guess when you read me...so nice 7th August.