15 Oct 2015 Feed Tags…. What do they tell us? How do we read them?
Walking into the feed store, looking at labels on horse feed can be quite confusing, if not intimidating. It should not have to be, but it is important you have a little background information in order to make a more sound and educated decision.
The first thing we usually get to see is the “Guaranteed Analysis”. What is that? According to the AAFCO or the Association of American Feed Control Officials, “… labels require a guaranteed analysis on the label to advise the purchaser of the product’s nutrient content. At minimum, guarantees are required for minimum percentages of crude protein and crude fat, and maximum percentages of crude fiber and moisture. The only exception is for products that do not and are not intended to provide protein, fat or fiber, in which case the product is exempt from guarantees for those components. In all cases, though, a moisture guarantee is required. Guarantees for other nutrients are normally voluntary, although additional guarantees may be required to support claims made on the label.” What does that tell you? Unfortunately the labeling laws are a little vague and do not really help us understand what we are looking at. Instead, we need to do a few calculations right off the bat.
If you think the percentages you are looking at are ‘absolute’, then that is a first misunderstanding. It is most important to also look at the quantities the manufacturer recommends you to feed in actual weight. The percentage is only a value based on that weight and only then can it become a meaningful value.
Feed 1 – 20% of nutrient X and you have to feed 2 pounds of it – results in 0.4 lbs
Feed 2 – 14% of nutrient X and you have to feed 5 pounds of it – results in 0.7 lbs
Comparing the two, one would think 20% is too high for whichever component you may be looking at, while 14% is acceptable. However, once calculating how much you need to feed of it will end up much higher in the 14% feed…
This is the only accurate and correct way to compare between feeds. There is however another caveat…
Let’s have a look at the first nutrient on the ‘guaranteed analysis’ list.
Crude Protein (CP)
This number represents the total nitrogen measured in the feed. This includes both true protein and non-protein nitrogen. In other words it is not a definite number to tell you how much protein is actually present because it may represent some nitrogen from non-protein sources such as nitrates and urea. It can be a misleadingly high measure of protein content. It also does not tell you anything about the source, type, quality and digestibility of the protein present. That is information only to be derived from the ingredients list of the feed.
Why have this information on the label? It is required by the USDA and state laws and has been the standard for many years before there was the science to analyze nutrients in more detail. A little more information on Protein and its role is in order to understand its importance in the diet of the horse. Protein is essential to the development and building of the body of the horse much more than it is a (often thought of) source of kinetic energy to the horse. Vital organs, such as heart, liver, kidneys and lungs are created with protein. Skeletal muscle is by far the largest storage of protein in the body. Blood protein, bones, eyes, skin, hair, hooves and connective tissue all are made of the amino acids found in protein. Last but not least, digestive enzymes and antibodies in the immune system are also made of protein.
Only when a horse runs out of all other sources of (kinetic) energy, will its body turn to the protein reserves to provide them with that energy. That will first be visible in the quality and appearance of the hooves, skin and hair, since the body will preserve its vital functions at all cost.
Building blocks of protein
The building blocks of protein are amino acids. There are 22 amino acids of which 10 are essential, because they cannot be produced by the body of the horse. They have to be present in the diet to supply them to the horse. Of those 10, there are 3 limiting amino acids, which you could say are the ‘most’ essential and usually the ones that are out of balance in feed: Lysine, Threonine and Methionine.
Back to labels
Some manufacturers will actually list the values of these limiting amino acids on the “guaranteed analysis” as a source of information to the customer and to ensure its presence.
Protein quality is determined by the profile of protein, its digestibility and its source. The combination of these characteristics determines the bioavailability of this nutrient and thus its quality.
- The profile in turn is determined by the presence of its building blocks (amino acids) and more specifically the amount and variety of the essential amino acids. All the necessary amino acids need to be present at the same time to make up a particular protein so the body can choose how to combine them from that ‘pool’. It is usually the ‘essential’ ones, which may be lacking and these thus determine its quality.
- The digestibility of the protein plays a role as well. When protein can be fully digested in the stomach and small intestine; it can actually contribute to the pool of amino acids the body can choose from.
- Here are some sources of the 3 limiting amino acids in different feeds:
(% based on Dry Matter Basis)
|Feedstuff||Lysine %||Threonine %||Methionine %|
|Soybean Meal (GMO)||3.08||1.90||0.67|
|Alfalfa Pellets (GMO)||0.8-1.0||0.8-0.9||0.2-0.4|
|Rice Bran (arsenic?)||0.66||0.52||0.29|
Although Soybean meal has a good combination of the limiting amino acids, it is made from GMO soybeans and has as such very negative effects on the health of the horse or any other organism. Copra, flax and Speedi-beet are all good sources of these amino acids as well and are all non-GMO.
The bottom line
Labels have federal requirements imposed by the USDA but one still needs to understand what is represented by the information at hand. Make the actual calculation when comparing feeds and more importantly read the list of ingredients. Ask questions! Be informed and you will be able to make a sound decision in the best interest of your horse.