In 1975, one sow in the US produced 720kg of pork per year but by 2009, it was 1,816kg per sow, points out Dr John Patience from the Department of Animal Science at Iowa State University. In 2009, the US produced 10.4 billion kilos of pork from about 5.8 million sows.

"Using 1975 productivity, it would require 14.5 million sows - an increase of 8.7 million - to produce 2009 quantities of pork," he writes in a report for the Prairie Swine Centre in Canada. "At an average sow feed cost of $336 per sow per year, the added cost of these sows, just for feed would be $2.95 billion per year, adding $26 to the cost of each pig sold."

The industry has been very focused on doing its job well. Technology has changed our world. Improvements in nutrition have made a major contribution to higher output per sow and improved efficiency in the nursery and grow-finish phase. Dr Patience lists the 10 top developments that have had the biggest impact over the last 20 years.

1. Transitioning from ingredient-based formulation to nutrient and energy-based formulation. "We are supplying nutrients to the pig, not corn or soybean meal," notes Dr Patience. "This has made a huge difference to the industry!"
   
   
2. Transitioning from empirical definition of requirements to factorial definition of requirements, leading to growth modelling. "The factorial approach says that the pig requires lysine for maintenance and lean growth, and calculates requirements based on assumptions about genetic capability, feed intake etc.," explains Dr Patience. "The new NRC model takes into account many variables when making recommendations."
   
   
3. Formulating diets on the basis of amino acids rather than protein, then later on the basis of Apparent Ileal Digestibility (AID) and now Standard Ileal Digestible (SID) lysine. This has made a huge difference as it is much more accurate. "For example, if we take the value for protein, total lysine and SID lysine in wheat as a baseline with the value 100, the comparative value of crude protein in corn would be 61 but the value for SID lysine would be 71. This illustrates how much the value is underestimated by using crude protein," says Dr Patience. "Similarly, for protein sources, we take soybean meal as having values of 100, canola meal has a value of 75 for crude protein but only a value of 60 for SID lysine, indicating that formulating on the basis of crude protein significantly overestimates its value to the pig."
   
   
4. The adoption of more sophisticated energy systems, which is currently Net Energy (NE). Traditionally, Digestible Energy (DE) or Metabolisable Energy (ME) has been used in formulation. DE is the gross energy in the ingredient less the energy in the faeces and is about 85 per cent of the GE. ME is the DE less the energy lost in the urine or gases emitted from the pig, which means we have about 82 per cent of GE. NE accounts for the energy lost by the pig as heat resulting in only 56 per cent of GE. "As we move towards NE we are removing most of the variation related to the ingredient and the variations after that are related to the pig and how it uses that energy," comments Dr Patience. "Ideally, we need to know how much energy goes for lean growth and how much goes into fat deposition but often we don't know that."
   
   
5. Adoption of the phytase enzyme and formulation of diets on the basis of available phosphorus.
   
   
6. The release of the 2012 NRC requirements, with a stronger emphasis on factorial as opposed to empirical approach to defining nutrient requirements. "This publication is now 400+ pages and has grown hugely, with a greatly expanded database of ingredient information," points out Dr Patience. "It attempts to make ingredient nutrient content more robust and places a greater emphasis on net energy and effective NE. Also, it tells you how many sources of data there are for each ingredient, so you can see how much validity to put on the data." In addition, he notes, it has an expanded emphasis on modelling to define nutrient requirements. A greatly expanded explanation of the scientific and philosophical basis of the recommendations presented in the book, helps you determine whether the approach is right for your farm.
   
   
7. The widespread availability of synthetic amino acids: lysine, methionine, threonine and tryptophan. "The use of synthetic amino acids reduces the quantity of soybean meal and other protein sources in the diet," explains Dr Patience. "It has been estimated that the widespread adoption of synthetic amino acids has reduced the quantity of land required to feed the US pig herd by 14 to 15 per cent."
   
   
8. Marker-assisted technology and hyper-prolific lines. "This has led to advances in productivity that could only have occurred if nutritional management was up to the task," believes Dr Patience. "Nutrition has kept up with genetics and we have been able to feed a sow that is producing 30 pigs per sow per year and also feed for the pig's better growth potential."
   
   
9. Adoption of increasingly sophisticated record-keeping systems, which have driven the decision making process. "This has had a profound influence on the industry. Producers ask a lot more questions when they have better data," says Dr Patience. "They ask: If I'm below average or below target, what is going on nutritionally?"
   
   
10. The increasingly rapid change in emphasis from maximising productivity to maximising financial returns. A good example is a big focus on barn throughput while meeting weight targets.

"How did we ever operate without using these developments?" asked Dr Patience. "Producers have adopted most of these although the NE system is not being used as much as it should. Least-cost formulation is only one step along the way, we need to know the pig's response so we can optimise its nutrient intake based on performance."

January 2013