Nutrient testing

Introduction

There are many factors that determine if, and how much of, an individual ingredient to include in a livestock ration. Such factors include:

• the complexity of balancing the ration
• availability of the ingredient
• the mechanics of feeding it,
• health and safety, and
• ultimate animal performance.

Feed analysis is the first step in ensuring proper ration formulation, with the goal of maintaining a healthy and productive livestock herd.

Analyze all feed sources to determine their nutritional value. This is the only way to assess the value and cost effectiveness of a potential feed ingredient. Next, design a detailed program to monitor consistency and ensure ongoing product quality.

When considering the use of alternative feeds in a livestock ration, pay particular attention to the nutrient content and consistency of the ingredient. Some alternative feeds, such as whey and pasta, are relatively consistent in their nutritional quality. Others vary widely in nutrient composition (e.g. bakery waste and confectionery products).

Some by-products are of so little nutritional value they either are not worthwhile alternatives to conventional feeds or may only suit specific livestock groups. For example, many cull fruits, or vegetables and processing wastes, are so high in water content their value is limited for most classes of swine. However, they may still be suitable as feed ingredients for dry sows or cattle. Before deciding which products to use, waste generators and livestock producers must know their nutritive value and variability in order to formulate rations to meet production goals. Obtain feed analysis from a reputable laboratory for information on any potential ingredient’s nutrient content. Repeated analyses can help determine nutrient variability.

Collecting a Sample

The most important part of any laboratory analysis is collecting a representative sample. The analysis will only be as good as the sample submitted. A small sample must accurately represent the entire load or batch.

To collect a sample for analysis:

• follow common-sense procedures, e.g. maintain clean hands and sampling equipment
• take at least 10 samples from several different containers or batches
• mix well in a clean bucket
• divide this sample in half and mix one of these halves again
• take a two-handful sub-sample from this final mixture.

Store collected samples in sealed plastic bags, removing as much air as possible to prevent moisture loss and sample deterioration. If the sample cannot be sent to the lab for several days, keep in the freezer. Minimize sample transportation time to ensure freshness. Samples must be labelled clearly according to the type of product, the date the sample was taken, as well as a contact name, address, and phone number.

Laboratory Analysis

Depending on the feed ingredient being considered, there may or may not be sufficient information to determine its suitability for feeding to livestock. For common ingredients and some products, such as milk by-products, apple pomace and chocolate waste, there is an abundance of information available on nutrient composition and suggested inclusion rates for livestock. In other cases, however, such as confectionary or grocery store waste, there may be little or no information. Many of these products are variable in composition and need to be analyzed frequently. Both the nutrient analysis and variability are important considerations for ration balancing.

Be aware that nutrient testing alone may not provide all the relevant information needed to make a decision. Depending on the product, additional analysis for toxins, pesticides, heavy metals, drug residues, additives, preservatives, microbiological contamination or other compounds may be necessary.

A nutrient profile helps identify the alternative feed’s classification. Feeds can be classified as:

• energy suppliers; e.g., corn, hominy, confectionary products, breakfast cereal residue
• protein suppliers; e.g., soybean meal, canola meal, tofu
• fibre suppliers; e.g., soybean hulls, cottonseed hulls
• medium-protein sources; e.g., brewers grains, distillers grains
• multiple nutrient sources; e.g. roasted soybeans, whole cottonseed
• fat sources; e.g., tallow, grease, chocolate by-products
• bypass protein sources; e.g., blood meal, fish meal.

An alternative feed can then be compared to a more common feed ingredient in the same class.

Table 1, Feed Analysis Laboratories (Current listings as of November 2002), lists feed analysis laboratories and some of the packages they offer.

A basic analysis should include, at the very least, dry matter (DM), protein (CP), calcium (Ca), phosphorus (P), salt and fat. Most laboratories offer packages that decrease the overall cost of the analysis if ordering a full profile. For example, packages that test for both DM and CP usually cost $12-$17. For individual analyses, expect to pay $6-$15 for minerals and $10-$15 for ether extract, which is the laboratory test for fat. For current pricing, contact the laboratory directly (phone numbers are listed).

Other analyses may also be necessary depending on the nature of the material being considered. Measuring pH is strongly recommended for alkaline or acidic feeds, such as potato waste or whey. Fibre needs to be determined in novel products to ensure balanced ruminant rations.

Understanding the Terminology

There are 2 types of analysis available for determining the nutrient content of feeds: wet chemistry and Near Infrared Reflectance (NIR). It is important to understand the difference between the 2 methods when considering the analysis of an alternative feed ingredient.

What is Wet Chemistry?

Wet chemistry is the preferred method for analysis of non-traditional feedstuffs because it more accurately measures the nutrient content. Analytical procedures are standardized for each nutrient test.

Advantages:

• Measures the nutrient content, does not predict it.
• Analytical procedures are the same regardless of the sample being tested.
• Easy to check for errors. Repeat analysis can be done on only the result that is out of line.

Disadvantages:

• Cost can be twice that of NIR tests.
• Turnaround time for analysis may be up to 1 week. However, some labs offer 24-hour turnaround to compete with NIR analysis.
• Different tests are done for each nutrient, allowing more room for human error. A reputable laboratory following approved testing methods standardized by the Association of Analytical Chemistry (AOAC) will minimize these problems.

What is Near Infrared Reflectance (NIR) Analysis?

NIR relates a sample’s reflectance of near infrared light to its chemical composition. It relies on prediction equations of nutrient levels, rather than actual measurements. Before any feed can be analyzed using NIR analysis, hundreds of calibration samples of the same feed type must be analyzed using standard laboratory wet chemistry methods and then tested using NIR. By relating the results from the standard analysis to NIR, a calibration set of data for the NIR instrument is developed. This is critical for accurate results. NIR analysis is not suitable for determining the nutrient content of most alternative feeds because information on the nutrient content of these feeds is limited and nutrient levels often are quite variable.

Advantages:

• NIR costs approximately half the cost of wet chemistry.
• Turnaround time is only 24 hours.

Disadvantages:

• Predicts the nutrient content, is not an actual measurement.
• Prediction equations need to vary for different feeds, growing locations and conditions etc. and must be continually updated.
• Equations for alternative feeds are not readily available.
• Equations are wide ranging. Accuracy depends on matching the equation to the specific feed being tested.
• One light reading is used to predict all nutrients. If one nutrient is out of line, it is difficult to determine if a testing error is the cause. Wet chemistry will then be required to confirm the nutrient in question.

NIR analysis is an inexpensive and rapid alternative best suited to analysis of hay, haylage, corn silage, high moisture corn and grains since prediction equations for these feedstuffs are plentiful.

What is Dry Matter?

The most important concept in assessing feed analysis results is the expression of nutrient content on a “dry matter” or “as fed” basis. All feed ingredients contain water, but some have more than others. (Consider the difference between orange pulp at 75% water and corn at 15% water.) The dry matter content of a feed is the most important component because it contains almost all of the feed nutrients. The amount of dry matter in a feed is simply:

% dry matter = 100 – % moisture

When comparing the nutritive value of different ingredients, it must be done on a dry matter basis for a valid comparison. To convert a specific nutrient from as fed to dry matter basis, use the formula:

(Nutrient content (% as fed basis) x 100) ÷ Dry matter content (%) = Nutrient Content (% dry matter basis)

To illustrate this, when comparing the protein content of orange pulp (2.2%) and corn (9%) on an as fed basis, corn appears to be a better source of protein. On a dry matter basis, however, orange pulp tests 8.9% crude protein, corn 10.6%. The as fed protein comparison, then, is misleading.

Sometimes it is confusing to convert as fed and dry matter nutrient values. A good rule of thumb is that the nutrient content expressed on a dry matter basis is always larger than the same nutrient content expressed on an as fed basis. This is because the as fed nutrient value is diluted with water.

Ration Formulation

Consult a qualified nutritionist to properly balance the ration using the results of nutrient testing. Rations based totally on alternative feeds will still require additional supplementation of minerals and vitamins and possibly other nutrients. Most successful by-product feeders rely on a mix of traditional feed ingredients and alternatives to meet their livestock’s nutrient requirements. Nutritional advice and ration formulation assistance is readily available through many feed dealers, premix companies, veterinarians and independent consultants.

Relevant OMAFRA Factsheets

For further general information on feed analysis and feeding, refer to the following Factsheets available from OMAFRA:

• Livestock Feed Terms Defined, Order No. 92-017
• Comparative Feed Values for Ruminants, Order No. 03-005
• Comparative Feed Values for Swine, Order No. 03-003

This Factsheet was reviewed and updated by Janice Murphy, Swine Nutritionist, Livestock Technology Branch, OMAFRA, Fergus.

Feed Analysis Laboratories (Current listings as of January 2016)

Contact these laboratories for available packages and proper forms to fill out.¹

A & L Canada Laboratories Inc.
2136 Jetstream Rd
London, Ontario N5V 3P5
(519) 457-2575
http://www.alcanada.com/Agricultural-Feed.htm

SGS Agri-Food Laboratories
Unit #1, 503 Imperial Rd N.
Guelph, Ontario N1H 6T9
(519) 837-1600
http://www.accutestlabs.com

Agribrands Purina Canada Inc.
127 Zimmerman St. S., P.O. Box 303
Strathroy, Ontario N7G 3W3
(519) 245-9600

Shur-Gain²
600 James St. South
St. Marys, Ontario N4X 1C7
(519) 349-2152

Stratford Agri-Analysis
P.O. Box 760, 1131 Erie St.
Stratford, Ontario N5A 6W1
(519) 273-4411 / 1-800-323-9089
http://www.stratfordagri.ca/view.php?Lab_Services/Feed_Analysis

Activation Laboratories Ltd. (Actlabs)
41 Bittern Street
Ancaster, Ontario L9G 4V5
(905) 648-9611
http://www.actlabsag.com/feed-analysis

Honeyland Ag Services
3918 West Corner Drive
Ailsa Craig, Ontario N0M 1A0
(226) 377-8485
http://www.honeylandag.com/feed-and-forage-packages/

¹. Legend of Abbreviations:

• ADF = Acid Detergent Fibre
• ADF-CP (ADF-N, ADICP, ADIN)= Acid Detergent Insoluble Nitrogen
• AP = Available Protein
• Ca = Calcium
• Cl = Chloride
• CP = Crude Protein
• Cu = Copper
• DM = Dry Matter
• DP (DIP) = Digestible Protein
• Fe = Iron
• HDP = Heat Damaged Protein
• K = Potassium
• Mg = Magnesium
• Mn = Manganese
• Na = Sodium
• NDF = Neutral Detergent Fibre
• NE_G = Net Energy (growth)
• NE_M = Net Energy (maintenance)
• NE_L = Net Energy (lactation)
• NIR = Near Infrared Reflectance Analysis
• NSC = Non-structural Carbohydrates
• P = Phosphorus
• RFV = Relative Feed Value
• S = Sulphur
• Se = Selenium
• SP (SIP) = Soluble Protein
• TDN =Total Digestible Nutrients
• UIP = Undegradable Intake Protein
• Zn = Zinc

^2. Accredited for testing certain nutrients through the Standards Council of Canada. For more details contact the Standards Council of Canada, (613) 238-3222.

Please Note: Each laboratory has its own “numbering” system for identifying the different packages and abbreviations for certain analyses.