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Mixing homogeneity of dry bulk and liquid amino acid sources

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by Christian Rabe, Applied Feed Technology, Evonik omogenously mixed feed is essential for livestock performance, as it ensures that all added nutrients are available within every feed ration. These essential and lowdosed ingredients, which include vitamins, trace elements, minerals and amino acids, must be available in the right amount within each

final feed pellet. The impact of mixing homogeneity, expressed as coefficient of variation (CV) on important livestock performance factors can be seen in this study, which was conducted with 240 Ross broilers in a 42-day grow-out period.

Factors that influence mixing homogeneity

The efficiency and the profitability of the production of live animals will be directly impacted by the homogeneity of mixed feed. With better feed homogeneity (10 percent CV vs 30 percent CV) there was a moderate improvement in feed intake and feed conversion rate. At the same time, flock homogeneity improved Table 1: Effect of diet uniformity on animal performance for broiler chickens (Ciftci and Ercan, 2003)

CV of 6th week BW [%]

Mixing Time [min]

0.2

0.59

3.75

CV Grower Feed [%]

30.4

11.3

9.8

Body Weight Gain 0 – 6 weeks [g]

2168

2191

2178

Feed Intake [g]

4131

4213

4067

Feed Conversion Rate

1.906

1.923

1.869

males [%]

9.5

8.1

7.4

females [%]

10.3

9.6

7.5

44 | April 2021 - Milling and Grain

significantly which is an important economic factor. As a rule, homogenous feed mixes with a CV of five percent or below can be technically achieved under commercial conditions and are considered as optimal for livestock performance. In this context, it is important that the analyte and assay which are being used for assessing homogeneity are suitable, sensitive, and accurate to pick up the variation. Table 2 contains the CV rankings of the feed additives found in finalised feed that is commonly used. In regular feed production, mixing homogeneity is sometimes not managed well. Of nearly 100 commercial feed mixers tested, approximately 51% had mixing CVs less than 10%, whilst 19% of the mixers had CVs greater than 20%. There are numerous factors influencing the mixing homogeneity of final feed. One important factor is the incorporation of liquids. Even below an addition rate of three percent, special care must be taken to achieve results comparable to the dosing of dry ingredients. The added liquids should be mixed longer than the dry ingredients to ensure homogeneity and to break up agglomerates that will have formed. There is the risk that if the dosing technique for liquid addition is suboptimal, small lumps might form which are not dissolved during the mixing process, eventually leading to larger agglomerations. To break up the lumps and increase mixing homogeneity, Table 2: The ranking for the CV of feed additives in finalised feed. Coefficient of variance (%) <5

Action required Optimum homogeneity advisable

5-10

Acceptable

>10

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