To establish a baseline of nutrient levels in swine rations and identify opportunities to reduce nutrient levels in feeds, commercial swine feed formulators who took part in the Manitoba Swine Nutrition Survey 2013 were asked about the methods they use to formulate swine rations.

Mathew Wiens, a landscape stewardship specialist with Manitoba Agriculture Food and Rural Development, says some formulators are basing phosphorus inclusion on standardised total tract digestibility but, it's relatively new and, although it appears to be the most precise way to formulate swine rations, it's not yet widely adopted.

Mathew Wiens-Manitoba Agriculture Food and Rural Development:

There's three approaches to formulating phosphorus levels in feeds.One is the total phosphorus, then the next one would be available, and not all of the phosphorus that's in the feed would be available to the animal.

Some is bound tightly in molecules, phytate molecules and a monogastric animal like a pig can't access that very easily and so then you want to know about the available phosphorus, and that would determine much more accurately what you should formulate toward.

That's the most common approach currently is to formulate to available phosphorus levels, but that doesn't mean that all of that available phosphorus is actually being digested, so then this digestible phosphorus approach takes it one step further, the standardised total tract digestibility approach uses methods to more accurately understand, of the available phosphorus, how much is actually being digested and used by the pig.

Mr Wiens says from here the hope is to provide workshops related to formulating phosphorus based on standardized total tract digestibility.