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Recommended Good Production Practices for medicated feeds contain a valuable summary of the things cattle producers should be aware of when they mix their own rations. If feeding medicated feeds, no one questions the need for some degree of standardization. Certainly mixers do vary in efficiency and mixing times. Research shows the optimum mixing time for a mixer can only be determined by testing the machine. We also need to realize that some mixers will not mix well regardless of the mixing time. If you are selling feed or mixing medications, it is good practice to determine the optimum mixing time by conducting an efficiency test.

This should be done at least once a year, or any time the mixer is adjusted, new parts are installed or procedural changes made. Mixer efficiency tests involve analyzing 10 sequenced samples taken between the initial and final discharge of a batch. The feed formula used and the ingredient or nutrient tested, such as a drug or salt, should be appropriate for the test. Consult the mixer manufacturer or the Canadian Feed Industry Association Quality Assurance Guidelines for additional information. Some feed laboratories have mixer efficiency test packages, as well.

A mixing checklist

Clearly identify feed formulas and keep them up to date.

Keep records of formulas in current and past use.

Ensure the feed-mixing formula clearly specifies the concentration of the microingredients used.

Make sure your staff are aware that many microingredients (vitamins, medications, trace minerals, selenium) may be purchased in several different concentrations. The product tags should be checked with the formula, especially when a new shipment is used.

Scales are sized to do the job they are intended for and are regularly checked for accuracy. The weighting accuracy of a hopper scale is about . One per cent of its capacity ( or two kg for a two-tonne scale). This is sufficiently accurate for weighing bulk ingredients but not for low-level additions such as vitamins, mineral or medicated premixes.

Microingredients are weighed using a scale designed to measure small quantities accurately.

All feed ingredient bins and microingredients are clearly identified.

Individual scoops are used for each product. Bags or bins of microingredients specify concentration of the product in addition to product name, where applicable. Product in unlabeled bags is discarded. Most or all bulk ingredients are added to the mixer before making any low-level additions. The mixer is not overloaded or used to mix very small quantities of feed.

Feed is mixed sufficiently. This is especially important when concentrated medications or micronutrients are added. (e. g. Rumensin concentrate instead of 32 per cent protein supplement containing Rumensin). Diluted premixes are safer to use for on-farm mixing than concentrated premixes, especially when mixer efficiency is not known.

To ensure product residues do not occur, make sure appropriate procedures (flushing, sequencing) are used when:

Mixing or feed-handling equipment is used for medicated feeds then non-medicated feeds.

Finishing cattle.

Medicated feeds

A limited number of animal health products are available for use in cattle feeds. These include several ionophores, such as Rumensin, Bovatec and Posistac. Ionophores can improve health by inhibiting the growth of the microbes that cause coccidiosis and improve feed efficiency or weight gain by selectively affecting microbial populations. Because of their mode of action on microbes, ionophores are considered antimicrobials but are not related to any antimicrobials used in human medicine. Other feed medications include a limited number of antimicrobials (tetracyclines and sulfamethazine); MGA, to improve feed efficiency in heifers; and a dewormer, Fenbendazole.

Medications can be added to feeds only under strictly controlled conditions, as laid down in the Compendium of Medicating Ingredient Brochures (CMIB).

More than one product may be used in feed only if both are listed in the CMIB, and if the compatibility of the combination is approved. A veterinary feed prescription is required in order to manufacture any medicated feed in Quebec, and in the rest of Canada when medications are used in any way other than approved by the CMIB.

Medicated premixes for use in feed must be kept in a secure, clean location. All containers should be clearly labeled with the name and concentration of the medication, and should have covers, or be otherwise protected against accidental contamination. A record log must be maintained for medication usage and reconciled with actual usage.

Sample records can be sourced from provincial co-ordinators for the Verified Beef Production Program.

The goal is to make Canadian beef the best in the world in terms of quality and safety. Everyone has a role to play in this, for quality starts when a calf is born and ends with a steak on the plate. The material in this series will identify areas for improvement and the steps we can all take to put Canadian beef over the top.



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