Lysine to Crude Protein Relationship 2009

The primary use for soybean meal is as a supplemental source of essential amino acids, such as lysine, in poultry and swine feeds. While today’s market emphasizes protein quantity as described by crude protein level, the swine and poultry nutritionists who determine how the majority of meal is used are also concerned with protein quality. Protein quality is related to the amino acid profile of a protein and the extent to which it can be utilized by an animal. Soybean protein is considered to be of a relatively high quality.

When formulating diets using conventional grains and proteins, achieving adequate levels of some nutrients represents more of a challenge than others. Such nutrients are often referred to as limiting when deficiencies result in poorer animal health and/or productive performance. For rapidly growing swine and birds, the essential amino acid lysine is an example of such a nutrient.

Soybean meal is a good source of lysine since it has both a high level of protein and the proportion of protein represented by lysine is relatively high as well. The relationship between lysine and protein is described by the Lysine to Protein ratio. In general, the higher the Lysine to Protein ratio, the better.

If the Lysine to Protein ratio varied to a very small extent, then crude protein level would be a good indicator of lysine level. Unfortunately, the relationship between crude protein level and lysine level is not strong enough to enable swine and poultry nutritionists to use crude protein as an adequately reliable indicator of lysine level.

The information presented below describes the extent to which the lysine to protein relationship varied within the USDA-NASS 2009 sample set. Information which follows is intended to help illustrate some of the implications of this variation.

Samples Provided by USDA-NASS for Crop Year 2009

Note: For table with individual district values, use this link: LCPR_Table_2009

Data Map for Observing Trends across Geographic Area

Information is presented by FIPS District. Each district is identified by a numeric code which is a combination of the respective state and district codes. As an example, district 1710 is District 10 in Illinois. The same code is used in the table of individual district values which can be accessed via the “LCPR Table 2009” link above.

The following data map presents average values, by FIPS district, for both crude protein and the Lysine to Crude Protein ratio. Presenting both together allows for a better sense of the relationship between the two criteria. Since there are multiple value-contributing components in soybeans, developing a better understanding of the relationships that exist between them is critical to determining approaches for their best use and improvement.

The values presented in the above data map are also presented in the following chart. As illustrated by this chart, the relationship between soybean crude protein level (protein quantity) and the lysine to protein ratio (a factor in protein quality) is weak.

Swine and poultry nutritionists utilize soybean meal and are thus interested in meal composition, not soybean composition. Estimating meal composition based on soybean composition is a challenge due to the multiple factors involved.  When trying to better understand complex systems such as this, models can be helpful. Models estimate outcomes associated with defined scenarios. The use of information from models must be tempered with the understanding that the outputs from models are estimates which are dependent upon the set of assumptions utilized. However, when critically viewed, such information can be useful in the development of valuable insights toward the identification of areas worthy of further exploration. The estimated meal lysine levels presented in the following chart are based on the use of a model which utilizes the compositional profile of each soybean sample.

The following chart plots the crude protein level of each soybean sample in the dataset against the estimated level of lysine in meal produced from a soybean bearing its compositional profile. Based on this set of results, and indicated by an R² of 0.44, a weak relationship exists between these two criteria. Note that the range for R² is zero to 1. The closer R² isto 1, the stronger the relationship between two criteria. To the extent that a relationship is defined by the black trend line, it is described by the regression equation presented immediately above the R².

The soybean protein threshold for producing high protein soybean meal ranges from approximately 35% to 36% protein, depending upon oil level. This threshold is outlined by the “red-box” in the above chart.

The average lysine level for the samples within the “red-box” is 3.11% with a standard deviation of 0.08%. Lysine levels within the “red-box” range from a low of 2.86% to a high of 3.34%. This level of variation in lysine has significant implications for the use of meal in poultry and swine feeds.

Actual vs. Attributed Lysine Values:

When formulating feeds, nutritionists must associate each ingredient that they intend to consider for use with a nutrient description. When the level of a given nutrient is consistent and/or known for an ingredient, assigning a value is rather straight forward. In the above example, if the nutritionist is able to determine the actual level of lysine in meal prior to formulating it into a feed, crystalline lysine can be used to compensate for any differences between lots of meal.

To illustrate, a ton of meal with 3.34% lysine contains 9.6 more pounds of lysine than a ton of meal with 2.86% lysine. This difference is equivalent to 12.2 pounds of crystalline L-Lysine HCL. The difference in applied value per ton between the two meals is the 12.2 pounds of L-Lysine HCL multiplied by the current market price for this feed ingredient. If not reflected in the price paid for the meal, the cost per finished ton of feed would be greater when using meal with the lower lysine to protein ratio due to the need to add more crystalline lysine.

When the level of a nutrient is known to vary and actual values cannot be determined prior to use, the nutritionist must attribute a value to the ingredient. This latter situation represents a risk.

If the actual value of lysine in the meal is greater than the attributed value, then more than the required level of lysine will be consumed by the animal. Apart from serving as an expensive source of energy, excessive lysine in the diet is of little value to the animal and thus represents an inefficient use of this resource. The applied and associated economic value of this excess lysine is wasted and thus lost to the overall system.

If the actual level of lysine in the meal is lower than the attributed value, the level of lysine in the formulated feed will be lower than what the nutritionist has determined to be optimal and animal productive performance can suffer.  Poorer productive performance can be far more costly than the cost of compensating for low meal lysine through the addition of crystalline lysine. An approach for managing this risk is to attribute a low lysine value to meal when the actual value is not known.

The level of lysine attributed to meal is a factor in the determination of its applied value. When the attributed value is lower than the actual value, soybean meal is both underutilized and undervalued. This lost value extends to what an end user is willing and able to pay for meal which extends to what a processor is able to pay for soybeans. The cumulative effect of the industry consistently under utilizing and undervaluing soybean meal is potentially huge.

In the above chart, the horizontal, dark green, dashed line corresponds to 3.02% lysine. This is the level of lysine attributed to high protein soybean meal in the “Feedstuffs Ingredient Analysis Table, 2010 Edition” which is part of the “Feedstuffs 2010 Reference Issue and Buyers Guide”, September 16, 2009. In the above set of data, 79% of the samples had estimates of meal lysine above this value. It must be noted, however, that the above estimates are for meal to which hulls have not been added back. When hulls are added to meal higher than 48% protein, which is reflective of industry practices, estimates from the model indicate that 76% of the samples will exceed 3.02% lysine. Soybean meal that delivers levels of lysine greater than that attributed to it by nutritionists is underutilized and undervalued.

Low Protein Soybeans:

Current trading rules focus on crude protein and allow for the assessment of a penalty when soybean meal is lower in protein than guaranteed. Since soybean meal protein is related to the level of protein in the soybeans from which it is produced, soybeans that do not allow for the production of high-protein meal are of lower value to the processor. As a result, soybeans grown in areas associated with the inability to produce high protein meal may be discounted.

In the above chart, soybeans to the left of the “red-box” and thus below 35% protein would be subject to potential protein discounts. This subset of samples represents 48% of the entire set of samples. A visual review of the chart indicates that of the samples below 35% protein, a considerable number appear to have lysine levels equal to or above 3.02%. This subset of samples represents 31% of the total set of samples. In other words, only 17% of the samples are both below 35% protein and 3.02% lysine.

Summary:

A disconnect exists between the current market which focuses on protein quantity and the needs of the largest meal end-user segment which also must consider protein quality. There is a cost associated with this disconnect. Better information and its use could offset this cost-of-not-knowing by allowing for a more efficient utilization of the nutrients provided by soybean meal.

A similar situation may exist for other nutrients provided by soybean meal. If so, then a market that values composition in addition to weight would not only allow for a truer pricing of meal based on its applied value, but also a more efficient utilization of this important resource. Pricing based on actual applied value would contribute to the competitiveness of soybean meal. A more efficient utilization of the nutrients provided by soybean meal would also contribute to the sustainability of soybean production.

 

Disclaimer:
All information provided on the U.S. Soy Measurements (USSM) content is provided “as is” and is intended for illustrative purposes only. No warranty, expressed or implied, is provided regarding any information provided on USSM content. All information is provided on the condition that users must make their own determinations regarding any use of this information and must assume all risk associated with any and all use.