3.6.4  Pellet durability index (PDI)

Texture of feed pellets is considered an important  criterion for the acceptance of compound cattle feed by milk producers. Cattle feed plants in routine test the feed pellets  for  chemical  composition,  but  not for  texture.  Sometimes,  the  feed  pellets are either  too  soft  or  too  hard,  much  to the  dissatisfaction  of   customers.  Texture of feed pellets largely depends upon the composition and mode of processing in the feed plant. Fineness of feed particles, fibre, fat and silica content in the formulation play important  role  in  the  quality  and  texture of feed pellets. Pellet durability tester is a useful device for testing the texture of feed pellets (Fig. 3.20). Take test pellets of diameters 9 to 20 mm, length up to 30 mm, totalling approximately

Fig. Pellet durability tester

100 grams. After testing, express the final weight as percentage of original weight to give the durability value. For example, original weight of pellets is 100 gm and the weight after testing is 97.5 gm. Thus, the sample has a “Pellet Durability Index” of 97.5 per cent.

Guidelines for using pellet durability tester

1.        Sample should be properly sealed, firm   and dust free.

2.        Minimum sample size is 1 kg.

3.        Two runs of 30 sec. are sufficient in duplicate sample.

4.        Select only premium pellet.

  5.        Clean the tester at regular interval