Articles and Resources

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):

Tags · Mixing · Mixer · Feed Mixer · Uniformity · Testing · Tracers

• Continue reading • Comments (0) 11.05.2009. 19:40

Ensuring Optimum Mixability In Feed Manufacturing: Part 2 - Effect Of Mixing Uniformity On Animals P

Effect Of Mixing Uniformity On Animals Performance

Uneven ingredient dispersion feeds may lead to reduced bird performance. In order for birds to reach their genetic potential for growth and meat yield, levels of protein, energy vitamins and minerals must be provided in their proper ratio. Duncan (1989) reported that as protein variation increased in feeds, growth rate and feed conversion were depressed (Table 1). A 10% variation in the feed quality significantly reduced both weight gain and increased feed conversion. When the coefficient of variation (CV) of the feed was increased to 20%, another significant increase was observed in feed/gain (F/G).

Tags · Mixing · Mixer · Feed Mixer · Uniformity · Testing · Tracers

• Continue reading • Comments (0) 11.05.2009. 17:45

Ensuring Optimum Mixability In Feed Manufacturing: Part 3 - Factors That Affect Mixer Performance

Factors That Affect Mixer Performance

Although insufficient mixing time and filling the mixer beyond the rated capacity are often implicated as common sources of variation in finish feed. Other factors such as particle size and shape of the ingredients, ingredient density, static charge, sequence of ingredient addition, worn, altered, or broken equipment, improper mixer adjustment, poor mixer designed, and cleanliness can affect the mixer performance (Wilcox and Balding, 1986; Wicker and Poole, 1991).

The mixing time necessary to produce a homogenous distribution of feed ingredients should be measured for each mixer. Mixing time is a function of mixer design and the rotational speed of the ribbon, paddle, or auger. Each mixer should be “tuned” to its proper Revolutions Per Minute (RPM) for optimum ingredient dispersion. Different types of ingredients may have a different flow pattern within a mixer at similar RPM’s. Generally, (Wilcox and Unruh, 1986), the higher the RPM, the faster the more efficient the pattern of dispersion (Figure 1). However, optimum RPM can change over the life of the mixer resulting from normal wear, ingredient buildup or structure basis to allow the mill operator to make the adjustments needed to achieve a high level of operational performance.

The size uniformity of the various ingredients that comprise the finished feed can directly impact final ingredient dispersion (Herrman and Behnke, 1994). If all the physical properties are relatively the same, then mixing becomes fairly simple. As the physical characteristics of ingredients begin to vary widely, blending and segregation problems are compounded. Large and small particles do not mix well and subject to directional influence in nearly any type of mechanical mixer. For example, ground grain with a particle size of 1,200-1,500 microns reduced the likelihood of uniform incorporation of microingredients compared to grain ground to an average particle size of 700 microns (Herrman and Behnke, 1994).

Tags · Mixing · Mixer · Feed Mixer · Uniformity · Testing · Tracers

• Continue reading • Comments (0) 11.05.2009. 10:46

Ensuring Optimum Mixability In Feed Manufacturing: Part 4 - Mixer Testing

Mixer Testing

Routine mixer testing should be an integral part of the quality assurance program and should be conducted quarterly. Procedures for mixer testing are relatively simple and involve taking samples at specific time intervals. The assay used and statistical treatment are relatively straightforward.

Tags · Mixing · Mixer · Feed Mixer · Uniformity · Testing · Tracers

• Continue reading • Comments (0) 11.05.2009. 09:48

Ensuring Optimum Mixability In Feed Manufacturing: Part 5 - Color-coded Tracers, Data Analysis

Color-coded Tracers

Microtracer™ Rotary detector (Micro Tracers, Inc., San Francisco, CA 94124): Inclusion and subsequent analysis for tracer particles is another method for mixer testing. A sufficient amount of iron filings, colored with a water-soluble die, is added to the mix to result in sixteen counts (particles) per sample, with the sample size ranging between 50 to 100 grams. The iron particles are demagnetized and sprinkled onto a large filter paper. The filter paper is then moistened with ethanol. When spots begin to develop, the paper is transferred to a preheated hot plate or oven and dried. All particles of the same color are counted, noting the total. Variation from the expected number is calculated to determine mixer performance.

Tags · Mixing · Mixer · Feed Mixer · Uniformity · Testing · Tracers

• Continue reading • Comments (0) 11.05.2009. 05:51