Interpreting the Feed Tag Part 1 - Understanding Crude Protein, Fat, and Fiber
The guaranteed analysis on a feed tag provides concentrations of specific nutrients. This is the information that should be used to correctly pair a concentrate with the type of forages being fed, to fully meet the horse's nutrient requirements. Feed manufacturers are required to list:
- Minimum levels of crude protein, crude fiber and crude fat (expressed as percentages)
- Minimum and maximum percentages of calcium (percent)
- Minimum values for phosphorus (percent), copper (parts per million or ppm), zinc (ppm), selenium (ppm) and vitamin A (International Units per pound)
Some companies may also list other ingredients, such as specific amino acids, biotin or Vitamin E, particularly if the feed is specialized to deal with a growth, metabolic or exercise related disorder, but these are not required to be reported on the tag. This blog post will center on the first three nutrients seen in a guaranteed analysis, crude protein, fat, and fiber.
Minimum Percentage – Crude Protein
Protein is added to equine diets to provide amino acids so that the horse can make other proteins in its body. It is not added to be used as an energy source. This is a major misconception in the horse world. Energy is calories and in horse feeds, carbohydrates and fats are the main sources. Energy or calories are needed to drive the biochemical process of making protein, as well as many other processes such as muscular contraction. Protein should not be used to judge the caloric density of a feed or how “hot” a horse feed is. Horses get “hot” or excited from many variables including but not limited to stress, being fed too much starch and sugar, being confined to stalls and not getting enough exercise, but not from being fed the correct amount of protein in their diets. Also, protein is not the cause of developmental problems in growing horses: rapid growth rates from excessive caloric intake, particularly from starch, nutrient imbalances such as too little protein or minerals and genetic predisposition are all factors in orthopedic disorders. Deliberately restricting protein intake, as with any essential nutrient, is counterproductive when attempting to correct growth, metabolic or exercise related disorders. For more information about protein please read our “The Scoop on Protein”
Protein comes in many different forms and it is important that the type used in horse feed provides amino acids that the horse can use. For example, cows can use feathers as a source of protein because the microorganisms in the rumen are capable of degrading the protein and liberating nitrogen, but horses have no such mechanism in their stomachs. A cow feed with the source of protein as feathers might guarantee protein at 12% which is accurate for a cow, but the same feed would be protein deficient for a horse. Source of protein is very important! Typically, soybean meal is used as the protein source in horse feeds. Milk proteins are also very available but adult horses cannot tolerate high levels of milk products in the diet as they are lactose intolerant. Steer clear of any product that uses meat or fish products as a protein source for horses. Not only are they less digestible but also very unpalatable.
Minimum Percentage – Crude Fat
Percentage of crude fat gives a good indication how energy dense the feed is. Fat contains nearly 2.5 times as many calories, by weight, as carbohydrate or protein. The higher the minimum percentage of crude fat, the higher the calories provided per pound of feed will be. Most grain-based concentrate mixes without added fat generally range from a minimum of 2 percent to a maximum of 4 percent fat. Many contemporary commercial feeds contain between 5 percent to 10 percent supplemental fat to help replace calories from starch. This is a much healthier way to feed calories to all classes of horses because high starch feeding is directly linked to colic, laminitis, performance disorders, behavioral problems and growth disorders.
Minimum Percentage – Crude Fiber
The crude fiber level on a feed tag can be an indicator of energy content. Insoluble Fiber provides little energy when compared to soluble carbohydrates or fat and serves mostly as bulk filler in the diet. Most grains are relatively low in fiber whereas forages are high in fiber. Grain fiber content ranges from 2 percent for energy-dense grains such as corn, to 12 or 14 percent for bulk grains such as whole or crimped oats that contain hulls (which are highly indigestible and are often seen in manure, though the oat itself has been digested). More contemporary rations with fiber levels higher than 10 percent include very useful forage and roughage products such as alfalfa meal, beet pulp, soybean hulls and rice bran. These “super fibers” are very soluble and easy for hindgut microbes to ferment. The resulting product, volatile fatty acids, can then be used by the horse to make glucose for energy, so these fibers are an indirect source of calories for the horse, not just filler.
Check back next time for part of 2 of Interpreting the Feed Tag where we will look at the minimum and maximum percentages of calcium, and minimum values for phosphorus, copper, zinc, selenium and vitamin A.
This blog post was originally posted on Wednesday, May 16th, 2012 at Equine Nutrition and Health Services Blog. Blog article was re-posted with permission from blog owner, all rights reserved.
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