The devices used in animal feed manufacturing most of the time yield a figure which
merely reflects a measurement which consists of a mixture of fragmentation and
abrasion, for instance the Holmen pellet tester. For practical purposes the aim should be
to identify the method which at best reflects the mixture of hardness and durability
which is most closely related to the figures derived from the specific plant at which the
feeds have been produced. For this purpose empirical equipment has been developed
which at present is commonly used in animal feed production: Pfost’s tumbling can, the
Holmen pellet tester and the Kahl hardness tester. Recently, on-line test devices have been developed for use during the manufacturing stage. Therefore variation in pellet
quality during a production run can be evaluated and subsequently used to adjust
pelleting conditions during manufacturing