Feed Mixing and Storage

October 10, 2012

Factors that Influence Stored Feed

• Moisture • Heat• Pests

Desired Moisture(when stored in aerobic conditions)

• Whole grains should contain less than 13% moisture.– Shelled corn can go up to 15.5%

• Ground and/or rolled grains should contain < 11%.

• Baled forages should be cured to contain 18-20% before being stored.

Facilitating Safe Moisture Storage

• Artificial drying – Disadvantage: can be expensive due to energy

costs• Field drying – crop remains in the field longer

– Disadvantage: weather losses/damage, predators, harvest loss, time in field

• Proper ensiling

Too much moisture

• Bacteria growth• Mold growth• Fungi growth

– Reduce palatability, alter nutrients, and produce toxins• Fermentation and heat = browning • Spoilage and nutrient destruction• Issues with caking• Spontaneous combustion risks

Pest Infestations• More common issue for grains rather than

forages. • Insects or rodents

• Damage may be grain destruction or contamination. • Feces and urine contamination 10 x more

than grain destruction or consumption• Reduce palatability• Increase risk of disease

Reducing Pest Issues• Store feed in rodent proof containers• Don’t store against the wall. Leave space. Off floor.

– USDA inspection issue• Empty and clean bins when not used. • Clean up spills. • Keep feed rotated – first in first out. • Get a rat terrier!!!

Mixing Feeds

• Most important thing is accurate formulations and proper weighing.

• Scales must be adequate and appropriate. • Scales should be maintained and kept clean, calibrated

on a regular schedule. • Conversions are a must-have skill.

– % to grams per ton, Lb to Kg, g to Lb, oz to grams• 16 oz per Lb• 453.6 grams per Lb• 1000 grams per Kg• 1 mg/kg = 1 ppm

Types of Feed Mixers

• Two major types– Batch Feed Mixers– Continuous Flow Mixers

Batch Feed Mixers

• Types– Vertical– Horizontal– Auger wagon

Mixers

• Comparing horizontal with vertical mixers: • Better for molasses and liquid ingredients.• Handle silage and ground hays better. • More expensive. • Require less mixing time. • Typically higher energy cost

Batch Mixers

• Stationary– Advantages: High accuracy, flexibility for mixing– Disadvantages: Feed needs transported to mixer,

storage, labor and energy costs • Portable

– Advantages: Convenient to producer, ease of transport, uses existing tractors for power, fenceline feeding, freshly mixed

– Disadvantages: Equipment tied up, labor and time, start up costs (renting or purchasing)

Continuous Flow Mixers

• Ingredients are simultaneously measured, ground and mixed.

• Advantages: automated, little space needed, accurate, may be more ideal for smaller situations and batch sizes.

• Disadvantages: No roughage, storage costs, energy costs, transporting costs associated with ingredients and finished mixes.

Mixing of Feeds• Order of ingredients added is EXTREMELY

important to the final mix. – Typical corn/SBM diets

• About 25% corn should be added first to “charge” the mixer.

• Followed by vitamin/mineral premix, additives, protein supplements.

• Followed by remaining grain. • Liquids should not be added at the very end but after

the critical additives (approximatley 60 – 70% of the mixing time)

Factors Affecting Mixing Efficiency

• Type of mixer chosen• Sequence of ingredients• Filling of mixer• Length of mixing time• Ingredient particle size• Ingredient density• Proper clean out

– Flushing with ground grain after mixing a batch

Interpreting Mixer Tests

• Assay for salt in multiple locations within the mix to determine the mean & standard deviation.

• Determine coefficient of variation (CV):– %CV = SD/mean x 100– < 10% CV is Excellent mixing– 10 – 15% CV = Good = increase mixing time by 25 – 30%– 15 – 20% CV = increase mixing time by 50%– > 20% CV = may need to re-evaluate other factors

ExampleLocation Salt (%)

1 0.24

2 0.51

3 0.55

4 0.42

5 0.59

6 0.55

7 0.59

8 0.59

9 0.64

10 0.55

Mean = 0.523Standard Deviation = 0.1156CV = (0.1156/0.523) x 100 = 22.10%

What would you do with this mix?

References• PDF Articles on Mixing

– Testing Mixer Performance – K State Extension– Sequencing of Feed Ingredients for Mixing – South

Dakota State University– Residue Avoidance Program – ISU Extension

• Book– Processing Feeds = pages 265-271– Mixing and Storage = pages 271 – 275– Laws and labeling (including collective terms) = pages

305 - 316

GA Requirements for Labeling