Fines segregation can be particularly bad when liquids such as fat and enzymes are applied post-pelleting because a higher percentage will be absorbed by the fines. Also, minerals tend to bind poorly to feed and may make up a greater proportion of the fines.
Feeding pellets allows animals to eat more and gain more. Pellets improve conversion of feed to meat, reduce waste, and assure that the intended nutrients are consumed with each bite. However, when fines are present in the feed, their nutrient content can differ from that of the pellets, a condition known in the industry as segregation.
Segregation allows nutrients to unmix.
Nutrient analysis was conducted on coarse and fine particles of a turkey crumble (Table 1). Samples were screened over a No. 30 sieve and fines were particles less than 600 microns. Protein was low in the fines and fat was high. Calcium and phosphorus were higher in the fines and almost all of the zinc was contained in them. Although this was a crumble, similar nutrient segregation is expected to happen when pellets contain fines. Not only will the nutrients unmix in the silo but segregation might also occur through selective eating. The more aggressive birds can consume the majority of the pellets and the late-comers will be left with fines. One way to reduce segregation is to improve pellet durability and thereby reduce the amount of fines.
Nutrient analysis of turkey crumbles
|Particle size, %