Ensuring Optimum Mixability In Feed Manufacturing: Part 1 - Introduction

Introduction

The daily ration of nutrients that an animal receives from a feed may vary from time to time due to a number of reasons. The sources of variation will probably cause variation in the day-to-day level of nutrition received by an individual animal. Certain nutrients are guaranteed to be present at minimum levels and regulatory officials will be concerned, if guarantees are not met. Certain ingredients may be toxic at very high levels. The nutrient variation in feeds is most likely to occur for the following reasons (Wilcox and Balding, 1976):

a. Variation in the composition or quality of ingredients from batch to batch or from time to time
b. Poor mixing or segregation after mixing
c. Errors during weighing or proportioning

In most cases, a sound quality control program can insure optimum feed preparation. Routine inspection of the mixer, proper mixer "tuning" , maintenance of all liquid systems and close attention to ingredient inventories will go a long way to ensure that the nutrient specifications prescribed by the nutritionist, actually reach the bird.

The consequences of nutrient level variation are varied. However, the major disadvantage of variation is normally the effect on animal performance.

Mixing is one of the most essential and critical operations in the process of feed manufacturing, yet it is frequently given little consideration. The objective in mixing is to create a completely homogeneous blend. In other words, every sample taken should be identical in nutrient content. A functional definition of uniform mixing can be summarized in one sentence. "All nutrients will be present in sufficient quantity in the daily feed intake of the target animal to meet its minimum growth requirements’’.

The literature is filled with classic examples of the impact of inadequate vitamin and mineral consumption on animal performance. However, field examples are rarely "classic" in nature, and are therefore, very difficult to diagnose. Unfortunately, in most cases the effect of inadequately/ improperly mixed feed manifests itself as marginally depressed performance. Typically, birds exhibit slight reductions in growth, feed conversion, feathering and other performance parameters. As a result, the technical staff of a commercial company may incorrectly diagnose a decease condition, and never resolve the underlying problem in the mill.