FERROMAGNETIC MICROTRACERS AND THEIR USE FOR EVALUATION OF THE HOMOGENEITY OF FEED FOR AGRICULTURAL ANIMALS AND POULTRY

The worldwide formula feed industry manufactures more than 900 million tons annually. Manufacturers waste labor, energy and capital when they mix feeds longer than necessary to achieve a complete blend. Excess mixing may also cause degradation of vitamins and medications. If feed is not completely mixed, portions of the feed will contain either too much or too little of the formulated ingredients. This excess variability causes economic losses to users of the feed and may increase the incidence of illegal drug residues. Periodic routine mixer testing is both economically and ethically justified. The mid-1990s brought an increased interest from regulatory authorities in many countries in assuring medicated feeds are mixed completely and that all micro ingredients are added as formulated. Feed manufacturers owe a response to the public to ensure their feeds are properly manufactured. This interest coincides with their self-interest to make the best product reasonably possible. This benefits the feed manufacturer's customers and the feed manufacturer himself if he is an integrated producer. By developing and implementing welldesigned sampling and analysis plans to document the efficacy of these manufacturing processes the feed manufacturer can validate his mixing and micro ingredient addition operations. Quality control mixing of feed is an integral part of the general system of control over the production of healthy food for people. This article is devoted to a wide variety of analytical ferromagnetic tracers used to assure the quality of mixed formula animal and poultry feeds. When formulated in vitamin, mineral or medicated premixes, a MicrotracersT r serves to mark the presence of the premix in the finished feeds as well as to identify the premix and feeds containing it as proprietary. Some qualitative results on this subject can be obtained with using Mason Jar procedure. When assayed quantitatively, a MicrotracersTMcan be used to document efficacy of mixing as well as adequacy of batch to batch “cleanout” of mixers and other feed manufacturing equipment. The application of Rotary Detector for quantitative separation of microtracer from the feed samples is described and use of Poisson and chi-squared probabilities for interpretation of mixer study results are presented.