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Cheaper Ingredients May Have Hidden Costs

It’s no secret that livestock producers have been dealing with high feeding costs.  Considering that feed is the largest part of the total cost of production, it’s no wonder that pork producers are looking for cheaper ingredients to lower diet costs.  In particular, distiller’s dried grains with solubles (DDGS; by-products of the ethanol industry) are abundant and relatively inexpensive, and thus, are frequently included in ration formulations as a source of protein and energy (oil).

The opposite approach can also be taken – use high-quality ingredients that will do one or all of the following:

  • Increase animal performance (growth rate)
  • Decrease feed intake relative to performance (increased efficiency)
  • Allow for easier risk management due to the high-quality nature of the ingredient
    • Such as a reduced risk of mycotoxin contamination, or nutrient variation

ExPress® soybean meal would be an example a high-quality ingredient – extruded, expelled soybean meal (SBM) with highly-digestible amino acids and energy.

Interestingly, a swine growth and carcass performance experiment by Kansas State University generated data that allows for the evaluation of these competing approaches to combating high feed prices (click here for the article).

The details are in the article mentioned above, but commercial diets were formulated using the following strategies:

  • Solvent-extracted SBM – represents a typical corn:SBM swine diet
  • ExPress® SBM – ExPress® SBM completely replaced solvent-extracted SBM; increased energy and fat
  • ExPress® + DDGS – DDGS partially replaced ExPress SBM and corn; energy equal to ExPress® SBM, but fat content was increased further, and total diet costs were reduced
  • DDGS + animal fat – ExPress® SBM removed completely, solvent-extracted SBM, DDGS, and 1.6% animal fat included; similar energy content but further increase in fat content (but with saturated animal fat, not unsaturated plant oils)
  • Low animal fat – No ExPress® SBM or DDGS; solvent-extracted SBM and 3.3% animal fat; slightly elevated energy content, but further increased in saturated fats
  • High animal fat – No ExPress® SBM or DDGS; solvent-extracted SBM and 4.7% animal fat; elevated energy content and saturated fats

The diets were balanced for total protein, ileal digestible lysine, and other nutrients as much as possible (except as just noted in the diet descriptions), and were fed to 120 growing pigs (106 lbs. body weight) for 83 days.  The groups of diets were slightly altered twice during the trial, but only to align the formulations with nutrient requirements as the animals grew.  For simplicity, I only used information from the initial diet because it was fed during the part of the experiment when growth was most efficient (and differences due to diet would be more prominent), and because the relative effects due to macroingredient (solvent-extracted SBM vs. ExPress® SBM, for example) were the same through the 83-day experiment.  For economic calculations, I used current information available to me (which changes over time, and will be different in other regions, of course), and only considered the macroingredients because the microingredients were essentially the same for all animals.  Growth performance, efficiency, and carcass quality were determined.

Although several calculations could be used to evaluate these commercial diets, days to reach the same body weight encompasses many things, including growth rate, and practical implications for a producer, such as labor requirements and group turnover rate.  This is shown below.

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As you can see, solvent-extracted SBM and ExPress® SBM – fed pigs reached 250 lbs. at nearly the same time (the solvent-extracted SBM group was 0.33 days faster), and adding DDGS to ExPress® SBM increased time to 250 lbs. by over 9 days.

Adding in macroingredient diet costs and feed intake, another picture emerges, which is shown below.

 

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The relative cost of feeding pigs from 106 lbs. to 250 lbs. was lowest when ExPress® SBM was fed.  Why was this?

  • When solvent-extracted SBM was used, feed intake was increased – more feed was consumed to match the performance of the ExPress® SBM group.
  • While DDGS lowered diet costs, the pigs were much less efficient and needed more time to reach the same body weight.  DDGS has a poor balance of amino acids.
  • Adding animal fat improved performance-losses associated with DDGS, but also added to diet costs (animal fat is expensive).
  • Adding animal fat alone certainly improved growth performance (indeed, the fastest-growing pigs were fed the “High animal fat” diet, and reached 250 lbs. nearly 4 days faster than ExPress® SBM – fed pigs), but added considerably to diet costs.

The last part is the carcass quality, which is shown below.

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Dressing percentage/lean percentage and body weight are perhaps the most important factors in determining how much a producer is paid – more live weight (with the different feed inputs, as we just discussed), and a higher percentage of the live weight that is useful.  As you can see, dressing percentage (and lean percentage) was not affected by any of the diets.  The iodine value of backfat is a measure of quality – too high iodine value in backfat, due to the presence of unsaturated fat in the diet, and pork products may not be firm enough, oxidize too quickly, and have a reduced shelf life.  ExPress® SBM did exhibit an increase in iodine value versus solvent-extracted SBM, and adding DDGS increased it even more – however, iodine values from 65-74 are considered acceptable.  So, even though DDGS has the potential to push iodine values higher (and possibly result in lower-quality pork), all of the carcass quality measures in the experiment were acceptable.

So, in conclusion, cheaper feed ingredients will certainly lower diet costs, but these savings may be wiped away (and may even result in higher production costs) when a more “big picture” approach is taken.