Author Lani Ritchey
CALIFORNIA CHINS
ONE STEP TO QUALITY FEED
Actually there are many steps to producing a quality feed. However
premixing is the first crucial step in quality control. It actually matters when and how something is added to a mixture. Cooking in the kitchen can illustrate problem when you add the ingredients in the wrong order or in the wrong condition ( solid instead of melted or egg whites separated from the yolk, etc.). Good feed mills should know their business but you can always ask them about their premixing practices. It might keep them on their toes!
Premixing is done to ensure proper distribution of vitamins, trace minerals, mold inhibitors, flavor ingredients, antibiotics and other prescribed medicinals and other products that are in small amounts. Premixing prevents dilute amounts from becoming airborne, electrostatically charged and cling to the mixer sides , migrate to"dead spots" in the mixer or clump into lumps.
Premxing can reduce the animal and human exposure to potentially harmful compounds by diluting them to approved safe concentrations. Grains that are contaminated with higher than approved levels of mycotoxins can be mixed into "clean" grain which in theory reduces the changes of getting a lethal( or at least illness causing) mouthful.
Premixing can standardize potency when using fermented products(some antibiotics, live microbial cultures and vitamins). The cooking illustration would be using regular white flour and cake flour in a recipe. Yes, both products are flour but they are quite different. Or using chilli pepper instead of black pepper, it changes the recipe quite a bit!
Careful attention must be paid to the premix process. The formulation, selection of carriers or diluents, use of dust control and binding agents, the mixer type, the sequence of ingredient addition (adding vitamins and trace mineral together will inactivate the vitamins), mixer cleanout ( how good is their housekeeping?), packaging and storage of the beginning and final products will affect the quality of the feed.
FORMULATION
Take formulation- the first mistake that can be made is human error. The custom formula could call for products that are incompatible. Does the feed mill use the formula as is or do they call the customer and say-your formula's ingredient list would mess up the potency of your vitamins or whatever ? A good feed mill would call, a so-so feed mill might say-its not our problem, just follow the formula.
Does the formulator consider the ingredient sources, bulk density, particle size variations, cost comparisons, handling characteristics, possible interactions and proper conversion of units(grams, ounces, pounds, kilograms and international units). They should consider these things.
Handling characteristics might be affected by humidity or temperature. Grain silo and feed mill explosions are the result of air-borne dust particles , low humidity and static electricity. Mills will dampen down grain and powder products to prevent a big bang. Does that affect the formula? It could.
There is a lot controversy on the interaction of vitamins and trace minerals.
How you handle and add those two premixes will affect the potency. Anitbiotics may also inactivate vitamins. So it can be very important as to "when" the ingredients are added together . It might be necessary to add more of certain ingredients to compensate for inactivation problems. But does the person who is measuring out the ingredients know how to convert or modify the amounts correctly? Improper conversion of measuring units can screw up the "cake". Try that in the kitchen- add a tablespoon of salt to something that requires a teaspoon of salt. Writing Tspoon, tspoon or tspspoon on the recipe card can be very misleading! Or using a 2 cup measuring cup instead of a 1 cup one. ( I baked fruit cake bricks with that mistake!)
How something is stored before, during and after a mill run is important.
If something is supposed to be stored in the refrigerator but isn't , the potency is lost. Equally bad for some product is direct sunlight/ultra-violet light, heat, moisture, rodent and pest infestation. If the feed has to wait until the client comes and picks it up, where will it be stored is a major question. Or is the feed to be delivered by the feed mill and stacked by feed mill employes or the customer's employees? Who is responsible until the customer signs off on the order? If it is being stored in exposured conditions, should you add more mold inhibitors?
CARRIERS AND DILUENTS
Carriers are supposed to assist in the uniformed distribution of fine-powdered microingredients. The most common ones are rice hulls, calcium carbonate, maize cob fractions and wheat middlings. The microingredient is added to the carrier , mixed throughly and then added to the bulk mixer. It is like mixing salt, baking powder into the sugar before adding it to the dough mix.. It is important that the carrier's nutritional value be added to the final ration. If you are using calcium carbonate, it is a source of calcium that must be factored into the calcium/phopshorus ratio. Also if you don't want any corn or wheat product (even if they are cob or middlings) in your ration, the feed mill should be aware of that.
Diluents extend or dilute the microingredients. Not suprisingly the same products used as carriers can be used as a diluent. Calcium carbonate is the most common one. Again the same warning about the nutritive value of the diluents applies. Good grain products can used as a dilutants with contaminated grain. The purpose is to reduce the overall mycotoxin level to a level the FDA accepts as "safe". (Safe for who?)
DUST CONTROL AND BINDING AGENTS
Grain silo explosions are not fun! So water, fats and oils are used to reduce dust and to bind the microingredients. They act as the adhesive which helps improve the holding( sticking) capacity of the carrier. They also reduce dust levels, reduce electrostatic charges, random loss of microingredients and help lubricate the equipment. The choice of what binder to use depends on several factors- cost, intended purpose of the premix, type of carrier, amount of carrier and religion. Water is cheap, mineral oil, vegetable oils are a bit more costly nad tallow(beef fat) and lard(pork fat) can land you in religious hot water. Fats and oils can cause problems if they aren't stabilized. They can turn rancid and destroy vitamins or cause an offtaste/offcolor in the feed. Whichever product you use, it should be in an aerosol droplet spray to evenly cover the dry material.
MIXING STEPS
There are two types of premix mixers- horizontal or rotary drum mixers. Housekeeping becomes very important here. You don't want 'carryover".
Your mixer needs to be able to handle a variety of bulk densities, produce less friction and heat( that can spoil the premix, esp. vitamins) but provide a large surface area to mix dry and liquid ingredients.
Ingredients need to be mixed in the correct order, it is recommended that the carrier (rice hulls, calcium carbonate, maize con fractions or wheat middlings) be put in first. Then as it is moving around in the mixer, add the binder (fat, oils or water) and the diluent can go in at any time. Then add the premix ingredients. Hopefully no oil balls will form in the mixture.
Carryover can be a minor housekeeping chore with terrible consequences if it is not done correctly. Mixers and other equipment do not empty completely. ( Think of the bowl after you have poured the cake batter out. That is "carryover" on the sides of the bowl.) It may be necessary for the equipment to be scrubbed out with brooms, brushes or air hoses. You can use rice hulls to flush the carryover out of equipment.
You don't want any presciption drugs or growth promoters of one species to be mixed into the next species' feed. It can be a deadly mistake or a costly one at least for the livestock rancher and feed mill. (Good advice from my feeds and feeding instructor was " Don't buy your feed from a multi-species feed mill. The risk of getting a carryover from another species' feed is too great" It is still practical advice today.)
PACKAGING AND STORAGE
If your premix is moisture, light or heat sensitive, or forms a vapor, thetype of packaging material(plastic, paper, cardboard, etc) used will vary. Vitamins are very sensitive to moisture, heat and light, so ultra-violet resistant and vapor barrier materials must be used. If the feed is going to be shipped , the packaging must conform to state, national or international regulations with the correct labels attached. Time is of the essence as some premix ingredients are not stable after 30 days. There have some studies that demonstrate that certain premixes can be stable up to 90 days.
Most feed mills will try to do a good job or mixing the premixes and adding them to the main ingredients. But things can go wrong and the consequences can be irritating, expensive or deadly for the livestock rancher. Protect yourself and your animals by asking questions about procedures .
REFERENCES
World Grain, Sept. 1996 ' PREMXING FEED INGREDIENTS" , pages 14,16, 17
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