Supplement labels: What are they saying?

When buying feed and supplements it is often difficult to understand the information on the label attached to the product. The information on a label is generally a combination of what has to be there legally and what the manufacturer wants to tell you about that product.

The example label below is similar to many labels on protein supplements.

Crude protein 30%
Equivalent crude protein 23%
Urea 8%
Calcium 8%
Phosphorus 4%
Salt 2%
Sulphur (S) 2%
Copper (Cu) 300mg/kg
Iodine (I) 30mg/kg
Zinc (Zn) 500mg/kg

Common ingredients listed on labels

Crude protein: The total amount of protein (which contains nitrogen) in the feed. Crude protein includes true protein (from protein meals, grain, etc.) as well as protein derived from urea and Gran-Am®. Crude protein may also be listed as protein and total protein.

Protein from urea and Gran-Am: Rumen microbes use the nitrogen from these products to form protein. This protein is referred to as microbial protein. The nitrogen from these products is referred to as non protein nitrogen (NPN) indicating that it has been derived from a source that is not a protein. The microbes also use the nitrogen from the true protein in grass, protein meals and grains to form microbial protein.

Equivalent crude protein: The proportion of crude protein that is derived from sources of NPN.

Urea: The total percentage of urea included in the ration.

Sulphur: Used by rumen microbes, in conjunction with nitrogen, to form some amino acids. Sulphur and nitrogen are required in the ratio of 1S to 10N.

Calcium: Included in most commercial licks although rarely, if ever, deficient in grazing cattle.

Phosphorus: An important ingredient in phosphorus deficient areas.

Salt: Generally included to control intake of the supplement. The higher the salt content the less palatable the supplement.

Other minerals: Included to maintain a mineral balance. Minerals are generally divided into two broad categories.

  1. Macro minerals – needed by animals in grams per day:
    – magnesium
    – potassium
    – sodium
    (calcium, phosphorus and sulphur are also macro minerals)
  2. Micro (trace) minerals – needed by animals in milligrams per day:
    – copper
    – cobalt
    – selenium
    – zinc
    – iodine
    – iron
    – manganese

Calculating protein in a feed

As explained on this page, Protein and urea supplementation, nitrogen, provided through protein, allows rumen microbes to break down the feed eaten by cattle.

The protein in any feed is calculated by determining the amount of nitrogen in that feed and multiplying it by 6.25. This formula can also be used to calculate the protein equivalent of urea and other sources of NPN.

For example:

  • Urea with 46% N x 6.25 = 287% protein
  • Gran-Am with 20% N x 6.25 = 126% protein

In the example label above, multiplying 8% urea (0.08) by 287 equals 23% (rounded), which is the amount of equivalent crude protein shown on the label.

This demonstrates that of the total 30% crude protein (in the example label above), 23% is made up from urea and 7% is from true protein such as protein meals or in some cases grain that have been included in the feed.

Comparing supplements

Supplement comparisons can be done by calculating how much each nutrient is supplied in an arbitrary weight of the product. For example, 100g of the lick (detailed above) will supply 30g of crude protein (mostly from urea) and 4g of phosphorus. This means that you would have to feed 500g of the lick per head per day to supply the recommended 150g of protein but only 125g per head per day to supply the recommended 5g of phosphorus.

Russ Tyler, formerly Queensland Government.

For more information see:

And watch the following two videos:

  1. How to understand your lick label. Step 1: Understanding the components (5:04)
  2. How to understand your lick label. Step 2: Calculating the daily intake of each ingredient (7:24)