Feed inspection: checking the composition using microscopy

Starting in January 2004 and following the changes in the regulations on animal feeds, producers of compound feeds will have to indicate all raw materials composing a mixture. The exact percentage of each component will also have to be indicated. Control authorities of the Swiss Federal Research Station for Animal Production in Posieux (RAP), have to check that these rules are followed both as regards labelling as well as the correctness of the composition compared with the declared content. Checking the composition of animal feeds is done by means of microscopy analysis of several fractions of a sample. Particles are determined and sorted, then weighed. The percentage of each product is calculated for the whole sample. This task requires an exhaustive knowledge of products and by-products used in compound animal feeds. To acquire this skill the microscopy laboratory of the RAP possesses literature and a collection of raw materials that are used for comparative studies. We show here the most frequently used components together with some of their microscopic characteristics. Some of the rarer materials and forbidden substances are also illustrated.