BANFF, Alta. – A European system assessing the net energy of livestock feed ingredients could help reduce ration costs and improve carcass quality.
Feed costs can make up as much as 70 percent of the hog production bill, with energy being the biggest expense.
Jean Noblet of the French nutrition company Inra helped developed a series of net energy equations over 20 years to formulate the most efficient diets for all stages of hog production. A wide variety of feed ingredients have been assessed and are used in the calculations, he told the Banff Pork Seminar on Jan. 17.
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The Dutch have developed a similar system for nutritionists to formulate better diets and reduce costs.
Net energy is the energy content of individual macronutrients found in a feed. Rather than measuring it directly, the industry calculates it from feed’s digestible energy or metabolizable energy content. ME content of a feed is the difference between digestible energy and energy losses through feces and urine. In growing pigs, the average energy loss is two to three times that of sows.
The energy value of feed is highly dependent on digestibility.
Technology such as pelleting or extrusion affects the energy content of a product. Processing usually improves available energy because it makes the fat more digestible.
This concept is more abstract than calculations used in North America, where digestible amino acids were considered more important than energy evaluations, said Robert Payne of the University of Alberta.
“Energy is a much more complex nutrient than others as it is derived from numerous dietary sources,” he said.
Data is lacking about the energy content of specific ingredients in North America. As a result, researchers such as Payne are attempting to develop a database of specific feed tables. They believe there are benefits in using net energy calculations to correctly rank the true energy of an ingredient.
One reason to make these changes is because net energy based diets potentially reduce the excess energy a pig would store as fat, which could improve carcass quality. It is also a good way to accommodate new byproducts such as distillers grain coming on stream. These are changing the way diets are formulated.
“Byproducts that are coming out now are forcing us to open up our textbooks again,” he said.
Net energy based diets are often lower in crude protein, which results in a reduced level of nitrogen in the manure and subsequently less pollution.
Protein should be used to add essential amino acids into the diet rather than relying on it for energy. Less protein could lower feed costs from a few cents to as much as $5 per tonne based on local prices.
The first step toward change is to develop a database to help nutritionists understand the ingredients and their roles in animal diets.
Next, nutritionists will identify all energy containing raw materials that would be used in grower-finisher formulas, starting with the smallest amount of ingredients so the formulation is not too complicated.
These diets would make up the bulk of the feed the pig consumes in its life. The idea is to supply the right amount of energy for the animal to grow optimally. Feed analysis must be kept up to date because values change.
The raw material to be used in the ration must be analyzed for crude nutrient content, including protein, fat, fibre, ash, dry matter, acid detergent fibre, sugar and starch.
Next, nutritionists will calculate the digestible energy and metabolizable energy values for each raw material using currently available NE prediction equations.
There are a number of equations available to assess energy values, so nutritionists should choose the equations that work best for each individual farmer. These new diets should be phased in over time.
See www.inapg.inra.fr/dsa/afz/tables to do your net energy calculations.
