2.3.2. Raw materials

More than 90% of the raw materials used in manufacturing compound feed are of plant or animal origin. Amongst these are maize, sorghum, millet, wheat or rice bran, groundnut or cottonseed cake, molasses, etc. which are of vegetable origin and fish meal, meat meal, bone meal, etc. which are of animal origin.

The remaining 10% are raw materials of mineral origin (salt, limestone, calcium phosphate, trace elements) or organic origin (vitamins, methionine, lysine and other synthetic amino acids, antibiotics, coccidiostats, anti-oxidants, etc).

The main characteristic of compound feed is its relatively constant humidity (between 9 and 12% maximum) content, with the exception of molasses. The compound feed industry therefore uses so-called “dry” constituents. Fresh products with a humidity content over 15%, such as the residues of various industries; brewer's grains, brewer's or distiller's yeast, waste from the citrus extraction industry, residues of industrial tomato processing, fish or abattoir waste, etc cannot be used without prior dehydration.

It must be borne in mind that the composition of these raw materials, i.e. their nutritional content such as: protein, fat, carbohydrate, cellulose, mineral substances, etc, is essentially variable. It must be remembered that any product of biological origin will not be standard as a manufactured product might be.

The composition of maize is different from that of wheat or millet. Maize composition may vary in the same production region depending on the variety grown and, with the same variety, from one region to another, depending on climatic conditions, type of soil and subsoil, fertilizing, harvesting and storage conditions, etc.

Mention should be made of premixes and mineral/vitamin concentrate. The latter contain premixes and mineral substances such as salt, limestone and calcium phosphate, while premixes contain vitamins, trace elements, anti-oxidants and sometimes prophylactic doses of medication (antibiotics, coccidiostats) and sometimes growth factors, anti-fungal agents and synthetic amino-acids.

Depending on their composition, premixes are used in feed at doses varying between 0.25 and 2%, while vitamin/mineral concentrates are used in proportions between 2 and 5%. Each premix or vitamin/mineral concentrate pack must bear a label indicating: the date of manufacture or use-by date, the nature of the ingredients and the proportion to be used in feed. The desired results will only be obtained by keeping strictly to the proportions recommended by the supplier. Responsible suppliers will provide feed manufacturers and users with effective technical assistance (analysis, formulation, feeding programmes, husbandry advice etc).

It may be worth mentioning that very strict rules must be observed by the supplier in relation to the composition of premixes or vitamin/mineral concentrates, in terms of the nature and quantity of ingredients; there are European regulations on the subject which are constantly updated by special commissions.