Quality control in feed production

by Teresa Acklin
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The production of livestock feeds deserves careful and professional attention.

By C. Reed Richardson

   Quality control in feed production is of utmost importance in the overall success and profitability of animal enterprises. No other factor directly or indirectly related to the proper nutrition and high performance of animals is more critical than feed quality control and ration consistency.

   The degree of quality is the consistency in which feed is formulated, processed, mixed and delivered as compared with what is expected. Animals thrive on a routine and respond better if the feed is low in nutrient variation and is similar in moisture content, texture and rate of energy availability. Quality control means knowing the quantitative amounts of all components, both the good and bad, in a feed.

   Usually, quality is verified by comparison with a known standard. However, relative values of quality over time are extremely valuable and useful in many situations.

   The relationship between feed quality and animal performance is important and encompasses not only the quantitative amounts of all feed components, but also the digestibility and metabolism of those components. Thus, the challenge for nutritionists and others involved in animal feed production is to consistently monitor all aspects of the feed production system and measure those variables that are good indicators of quality control.

   For the feed industry, a quality control system is the responsibility of management and involves personnel being properly trained to ensure a high level of organization, documentation and the policing of various procedures and processes necessary to guarantee the basic quality of feedstuffs and feeds.

      Sampling and Analysis

   Quality control of incoming ingredients is crucial to predicting the quality of a complete feed, supplement or premix. An important first step is accurate sampling and complete examination of the ingredient prior to unloading. Sampling and inspection procedures need to be in writing and should be maintained in a “Quality Control Procedures Manual.”

   The goal in sampling any lot of ingredients or finished feed is to obtain samples that are representative of the lot in question. A wrong answer — which may arise from incorrect sampling, incorrect handling of samples, analytical error, etc. — is worse than no answer. Thus, it is our responsibility to know proper procedures and techniques for sampling to be sure that correct formulations can be made.

   The accompanying table lists suggested sampling procedures for bulk ingredients and mixed feeds, bagged ingredients and mixed feeds, hay and syrups and fats. Establishing a retention schedule is recommended for all ingredient and mixed feed samples.

   Separate analytical analyses for quality should be routinely performed on samples of all materials used in feed manufacturing. These materials include water, grains, roughage, silage, protein supplements, mineral mixtures, vitamin premixes, molasses and fat and specific drugs.

   As a starting point for insuring quality in feedlot rations, all incoming feed ingredients should be quality checked for moisture, color, off odor, presence of foreign material, texture and uniformity and evidence of heating and deterioration due to biotoxins. More detailed analyses are performed on individual feed ingredients for the purpose of feed formulation and sometimes before the purchase of commodities if this information is not provided by the seller.

   Analyses that usually are considered to be routine for the different feed ingredients include:

   • Grains — grade, moisture, protein, ash

   • Grain by-products — moisture, protein, ash

   • Dry roughage — moisture, protein, ash, acid detergent fiber

   • Silage — moisture, pH, temperature, protein, ash

   • Protein supplements — moisture, protein, ash, non-protein nitrogen

   • Mineral mixtures — moisture, specific nutrients

   • Molasses — moisture, ash

   • Fats — moisture, free fatty acids, impurities, unsaponifiables.

   An overall evaluation of feed quality delivered can be derived by determining the variation in the four major areas that affect feed consistency. These four areas are variation of incoming ingredients, variation in feed mixing efficiency, variation in efficiency of delivery of mixed feed from mixing point to the animals and variation in analytical procedures


   Managers of a feed mill have an obligation to uphold Good Manufacturing Practices. The use and endorsement of appropriate and proper procedures and practices in the production of feeds do not cost the feed industry, they pay dividends.

   The feed mill manager is a key individual involved in the daily activities associated with the management of people, facilities and resources. Proper management ensures that the procedures appropriate for the production of feed are enforced. The feed mill manager, as well as supervisors and the people working under their direction, has an obligation to the animal food industry to maintain high quality standards in the production of feeds for animals, which provide meat, milk and eggs for the consumer

   Good Manufacturing Practices (GMPs) have been published in the United States and a number of other countries. GMPs deal specifically with the manufacturing of any feed containing one or more drugs, which is considered a medicated feed. The feed mill management should have written instructions that cover GMPs and quality assurance programs.

   GMPs cover all areas involved in the production of feeds, including personnel, facilities, feedstuffs, quality assurance checks, inventory control checks, processing methods, mixing procedures, finished feeds and feed delivery. Although commercial feed mills that produce and sell a complete line of feeds to the general public have a somewhat greater task in assuring quality and prevention of cross contamination of drugs, the obligation to assure quality in all feed mills is still great.

   Personnel training is essential and should be conducted periodically to assure compliance with procedures and insure quality of feed produced. These meetings usually are helpful in establishing and maintaining good morale and teamwork among personnel.

   The feedmill and adjacent buildings must be of suitable construction to minimize access by rodents, birds, insects and other pests and must be located in an area that will allow proper drainage. The building and grounds should be maintained as needed to assure a clean work place for personnel and for the production of feeds. Litter, refuse, improperly stored equipment and supplies are hazards and should be removed.

   The building must also provide sufficient space for facilities and personnel to perform their jobs properly. Examples for the production of medicated feeds include:

   1. appropriate area for receiving and storing of ingredients and drugs

   2. adequate space for grain processing, etc.

   3. appropriate space for feed mixing

   4. reserved area for equipment maintenance.

   Equipment must meet safety standards and be properly installed. All scales and metering devices must be tested for accuracy upon installation and at least once per year thereafter. Equipment must be constructed and maintained to prevent lubricants and coolants from contaminating ingredients or feeds. Excessive spills, leaks and dust problems must be prevented.

   Ingredients should be systematically monitored for quality factors throughout the entire process of purchasing, receiving, sampling and handling. All ingredients should be inspected for any abnormality that may result in a quality risk when added to the feed, and representative samples should be taken for assays. During handling of ingredients, care must be taken to prevent contamination.

   Drugs and premixes require special handling and record keeping. Records on drugs received must show the following information:

   1. name of drug, including potency

   2. date received

   3. amount in kilograms

   4. supplier's name

   5. supplier's code for drug (if applicable)

   6. supplier's lot or code number

   7. return of any damaged or unacceptable drugs.

   Other procedures that must be followed in the storage, handling and use of drugs include:

   1. Check each drug for identification. Do not accept unless properly identified.

   2. Keep all drugs and premixes stored in a neat and orderly manner for easy identification. It is preferable to store drugs in a separate room.

   3. Each bag or drug container must be coded with the supplier or company code for that drug.

   4. Packaged drugs in the storage area must be stored in their original closed containers.

   5. Check bags for tears and any other abnormalities. Do not accept any drugs that are not in good condition.

   6. Drugs in the mixing area must be properly identified, stored, handled and controlled to maintain their integrity and identity.

   7. Clean up any spilled drugs immediately, dispose of properly and record in the Drug Inventory Record.

   8. Use a separate scoop for handling each drug.

   9. Drugs and premixes must be used on a first received basis.

   A daily inventory of drugs and premixes is required. The Drug Inventory Record should be completed at the end of each 24 hour period. One should check usage of each drug against medicated feeds produced.

   The drug container should be weighed before it is opened and every kilogram of drug must be accounted for in usage or adjustment. (If a 20-kg bag was purchased but the drug amounts to 19 kgs, then list a 1-kg adjustment). Other adjustments could be related to improper weighing, spillage or product going out of condition.

   Cleaning, processing and mixing of feed ingredients require that personnel involved are thoroughly trained and properly supervised. Considerations for proper GMP's include the following:

   1. screening of grains and use of magnets

   2. uniform grind

   3. proper amount of steam, temperature and roll tolerance for grain flaking

   4. standardized mixing directions (Certain mixed feeds may require specific directions.)

   5. prevention of contamination

   6. checking for accuracy for all scales used for weighing ingredients (including drugs) at least once per year.

   Complaint files for medicated feeds are required in some jurisdictions. Files should include the following:

   1. date of complaint

   2. complainant's name and address

   3. name of feed

   4. lot or control number or date of manufacture

   5. specific details of the complaint

   6. all correspondence

   7. description of investigation

   8. disposition of complaint.

   The production of livestock feeds is big business. With this enormous opportunity comes the responsibility of management to produce safe, quality feeds that meet nutrient specifications.

   C. Reed Richardson is director of the Center for Feed Industry Research and Education, Department of Animal Science and Food Technology, Texas Tech University, Lubbock, Texas, U.S.

Sampling procedures for feed quality control


   • Take a minimum of three, 2.25-kilogram samples.

   • Each sample should be the composite of several cores taken randomly from

    the delivery truck, bulk storage bin or feed bunk, as applicable.

   • Duplicate determinations are recommended for all variables measured.


   • Use slotted feed trier for sampling and take 0.50 kg samples.

   • For lots of one to 10 bags, sample all bags.

   • For lots of 11 or more, sample 10 bags.

   • Analyze a minimum of three samples and average the results.


   • For chopped hay, take 10 samples per lot.

   • For cubes, take 40 cubes from a given population.

   • For bales, take one 30-to 45-cm core from the end of 40 bales in a

    given population.


   • Use a continuous flour sampling procedure at the point of delivery or a

    core liquid sampler.

Quality control checklists for feed manufacturers

   Potential sources of high or low analytical values

   • formulation error

   • nutrient or drug instability

   • moisture pickup or loss

   • incorrect weights (batching errors)

   • dust losses

   • non-uniformity of ingredient, supplement or premix

   • insufficient mix time

   • residues and cross-contamination

   • inadequate sampling methods

   • segregation in transit or of sample

   • analytical errors

   • “masking” effects of certain ingredients

   Assuring overall system efficiency

   • selection of intelligent and responsible suppliers

   • selection of intelligent and responsible mill operators

   • selection of adequate mixer

   • adequate mixing times

   • proper ingredient formulation

   • use of appropriate feed binders

   • limit conveying of premix and finished feeds

   • accurate weighing equipment

   • cleanliness and good housekeeping

   • accurate record-keeping

   Performance measurement

   • evaluate variation of incoming ingredients

   • evaluate mixer efficiency

   • evaluate efficiency of conveying feed from the mixer to the feed bunk

   • assess variation of analytical procedures