Quests for information may take us to the internet, reference books, electronic media or someone with the right expertise. But when it comes to livestock feed, almost all the information we need can be found in one handy place: the feed tag.
The basics by law
Any commercial feed sold in the U.S. must be accompanied by a tag that gives:
• The product name or brand name
• A purpose statement—the class(es) of animals and feeding situation(s) the feed is appropriate for
• Feeding and/or mixing directions
• Guaranteed analysis, or chemical composition, stating the levels of specific nutrients guaranteed by the company
• Ingredient listing
• Appropriate cautions or warnings
• Manufacturer or distributor name and address
• For medicated feeds: specific purpose, directions, name and concentration of active ingredients, and relevant warnings regarding withdrawal periods and misuse.
Why do some tags list more guarantees than others?
The only legal requirements for dry feeds are crude protein (if the feed is intended to supply protein), minimum crude fat and maximum crude fiber. Liquid supplements must also give percent dry matter. If a feed consists of more than 6.5 percent added mineral sources, beef feed tags must also guarantee minimum and maximum calcium, minimum phosphorus, minimum and maximum added salt (NaCl), and minimums for magnesium (Mn) and potassium (K). Other minerals and vitamins are
added at the feed company’s discretion.
Why do tags have a non-specific listing in the ingredient panel?
The feed manufacturer may use approved “collective terms” to represent some of the major ingredients being used. For example, “molasses products” on a feed tag could represent cane molasses, beet molasses, beet pulp, condensed molasses fermentation solubles, etc. Collective terms allow the company to reformulate in response to changes in ingredient availability or relative price without changing tags, or to use the same tag for multiple plants that differ in regionally available ingredients.
Can I assume the first ingredient listed is present at the highest inclusion rate?
Actually, no. This regulation differs from labeling requirements for human food. Many companies do list ingredients from greatest to least amount present, but are not required to do so.
What does the non-protein nitrogen statement mean?
If a ruminant (e.g., cattle, sheep) feed provides a portion of the guaranteed crude protein as non-protein nitrogen, or NPN, the guaranteed analysis section will include a line for “maximum CP equivalent from NPN.” Common sources of NPN include urea, ammonium polyphosphate, glutamic acid fermentation product, ammonium sulfate and ammonium chloride. It is critical to remember this number is given in crude protein equivalents and is based on the assumption that protein averages 16 percent nitrogen. Since NPN sources contain greater concentrations of N, some simple math is required to know how much of the ingredient is present. Take, for example, a tag listing a maximum of 28 percent CP equivalents from NPN that shows urea as the NPN source. Since urea is 45 percent nitrogen, and 45÷16 percent = 282, urea is essentially 282 percent crude protein. The guarantee (28) divided by the percent CP (2.82) gives us 10, meaning the maximum level of urea in the formula is 10 percent.
Reading between the lines
We can learn more from a feed tag than the directly stated information. These additional calculations and observations can be invaluable when comparing products. The smart shopper knows to look at the following values:
Units used to express guarantees: If feed X guarantees 30,000 IU/lb of vitamin A, and feed Y claims 40,000 IU/kg, these values must be expressed in the same units before a comparison can be made. The kg-to-pound conversion is 2.2, so feed Y actually has a lower concentration of vitamin A (40,000 ÷ 2.2 = 18,182 IU/lb).
Figuring daily cost: Expected daily intake must be considered when comparing different supplements. If mineral A costs $500 per ton, and mineral B “only” costs $250 per ton, which is the better buy? If the recommended daily feeding rate for the two products are 3 oz. and 8 oz. respectively, more money would actually be spent on mineral B.
Managing nutrient availability: Just because a lab can determine the presence of, say, an essential trace mineral, that doesn’t mean it is available for the animal to use. If you are counting on a feed to supply specific nutrients, it is important to evaluate the potential sources as listed in the ingredient panel. In the case of trace minerals, remember that bioavailability of TM typically ranges highest to lowest for organic, sulfate and oxide/chloride sources, and is usually even lower for minerals that happen to be present in other ingredients used in the formula.
What isn’t there: People can be surprised that there is no mention of energy per se on a feed tag. But “energy” is not something that can be readily quantified; even energy values provided in a lab analysis are calculated numbers, based on things like protein and fiber. And, especially in the case of ruminant animals, the actual yield of energy from a feedstuff can vary significantly depending on the overall diet and level of total feed intake.
Your feed tag can’t tell you much about product quality, consistency (other than excessive use of group terms), or manufacturing processes, either. If these things are important to you, your information search will need to encompass company reputation and personal experience as well as that handy feed tag.
Dr. Cathy Bandyk is Cow/Calf and Stocker Cattle Nutritionist & Product Manager for QLF, Dodgeville, WI.