Phosphorus Utilization and Excretion in Pig Production

Phosphorus deficiency is known to result in depressed growth and bone abnormalities in pigs ( Sus scrofa ). As such, practical pig feeding recommendations have over the years aimed at ensuring that pigs would not suffer from P deficiency. This means that a large safety margin has normally been included into the P feeding recommendations in order to compensate for variation in P digestibility in feedstuffs and feed phosphates. However, increasing attention has been devoted to the utilization and excretion of P in pig production over the last decade. Because of the continuous accumulation of P in soil supplied with manure, P utilization and excretion is a matter of great concern, especially in intensive pig‐producing countries, but recent research has shown that it is possible to reduce the P content of manure without affecting pigs' health and productivity. Several aspects have to be addressed. First, it is necessary to identify the content of digestible P rather than total P , since this will give a more precise basis for determination of P requirements for each specific pig category (sows, piglets, and growing‐finishing pigs), allowing safety margins to be reduced. The introduction of digestible P will also enable pig farmers and feed manufacturers to formulate diets that contain the exact amount of digestible P needed by pigs. Phosphorus digestibility in feedstuffs of plant origin is often low, so another approach is to render the intrinsic P more available for pigs. This will reduce the necessity for the addition of extra P as inorganic feed phosphates to pig diets.