Livestock Feed Analysis

• Feeds and forages contain nutrient components related to feed analysis values
• Livestock feed analysis services are available from agricultural diagnostic service centers and commercial laboratories

Glossary of Terms

• Antioxidants are feed additives to prevent oxidation of fats, which can cause rancidity
• Macrominerals are minerals found in an animal's body in concentrations greater than 100 ppm
  • Macrominerals include calcium (Ca), phosphorus (P), magnesium (Mg), potassium (K), chlorine (Cl), sodium (Na), and sulfur (S)
  • Represented as a percentage of dry matter
• Microminerals are minerals found in an animal's body in concentrations less than 100 ppm
  • Microminerals include copper (Cu), iron (Fe), zinc (Zn), selenium (Se), fluorine (Fl), manganese (Mn), cobalt (Co), iodine (I), molybdenum (Mo), nickel (Ni), and silicon (Si)
• Monogastric digestive systems consist of one stomach
  • Examples include humans, swine, poultry, horses, rabbits, dogs, and cats
  • Monogastrics have limited ability to digest fiber and non-protein nitrogen sources
  • Dietary starch and amino acids are essential for monogastrics
• Ruminant digestive systems consist of a multi-compartmental stomach
  • Includes a forestomach (rumen, reticulum, and omasum) and an abomasum (true stomach)
  • Ruminant animals include cattle, sheep, goats, buffalo, and deer
  • Ruminants have the ability to digest fiber and use non-protein nitrogen sources
• Non-protein nitrogen (NPN) is a fraction of the "crude protein" value that refers to any nitrogen (N) not in the form of amino acid chains
  • NPN examples: ammonia, ammonium phosphate, urea, and dietary nucleic acids
  • NPN is effectively used by ruminants with a functioning rumen with a readily available dietary carbohydrate source
• True protein consists of long chains of linked amino acids
  • Necessary for monogastric diets

Feed Component Analysis and How to Interpret Results

• Livestock produce more when fed a ration that meets their nutritional needs
• Laboratory analysis of feeds is the best way to formulate rations
• Feed analysis data determines the nutrient content of the ration
• Feed analysis data helps decrease feed costs and allows for efficient utilization
• Feed analysis helps producers evaluate forage production
• Feed analysis sets and monitors nutrient standards for local and imported feeds/by-products

Moisture and Dry Matter (DM)

• DM is the percentage of feed that isn't water
• Fresh grass has higher moisture and lower DM than hay
• DM increases with plant age
• Lower DM, more moisture, lower nutrient density so high moisture is bad for feed quality

Ash (Total Inorganic Matter)

• Ash measures total mineral content but not specific minerals
• Ash is not digestible
• High ash dilutes nutrients
• High ash can be from bone content from animal origin or soil contamination

Crude Protein (CP)

• CP estimates protein level via nitrogen content
• CP does not give individual amino acid profiles
• CP content peaks at 4-6 weeks then declines
• Legumes are higher in protein than grasses
• Seed oil meals have high CP values
• Compare feed costs on CP per pound of dry matter
• CP has true protein and non-protein nitrogen used by ruminants

Ether Extract (EE)

• EE (Crude Fat) measures fat and fat-soluble components
• Pigments and fat-soluble vitamins are included in EE, but amounts are not specified
• EE is usually higher in meat, fish, and whole seeds
• Fat can cause rancidity, low palatability, and toxic effects
• Antioxidants like Vitamin E are used to prevent feeds from becoming rancid

Crude Fiber (CF)

• CF is the poorly digested insoluble carbohydrate remaining after boiling sample in weak acid and alkali
• Made up of plant structural carbohydrates such as cellulose and hemicellulose, and some lignin

Neutral Detergent Fiber (NDF)

• NDF is the percent of total fiber in the feed
• NDF includes cellulose, hemicellulose, lignin, silica, insoluble CP, and ash
• NDF content increases as plants mature
• High levels of NDF limit intake
• Minimum levels are required to prevent fattening and to maintain healthy rumen

Acid Detergent Fiber

• ADF is the percent of least digestible parts of cell walls like cellulose, lignin, silica, insoluble CP, and ash
• ADF increases as plants matures
• Higher in legumes than grasses of same age
• Affects a feed’s digestibility - the lower the ADF content, the higher the digestibility

Cellulose

• Cellulose is the main constituent of cell walls
• Cellulose digestibility is high for ruminants, moderate for horses and rabbits, and poor for swine and poultry

Lignin

• Lignin is not carbohydrate, is a protective coating on the cellulose-hemicellulose structure of plant tissues
• Lignin is found in straws, hulls, and over-mature hay
• Lignin has no known nutritive value, except as a bulk factor

Nitrogen Free Extract (NFE)

• The NFE is made up of readily available carbohydrates, such as sugars and starches
• The NFE fraction in grain can be utilized by livestock but it is less available in forages and roughage