University of KentuckyCollege of Agriculture
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Feed: Sample Tolerances

 

Regulatory officials use analytical variations (AVs) as a guide for issuing any type of violation of the label guarantee. The total variation sur- rounding an analytical analysis of a feed product and comparing it to a label consists of (1) variation associated with the formulation and mixing in producing a feed, (2) variation of particle sizes in feed ingredients, (3) potential in gradient settling during transport, (4) variation associated with sampling, (5) variation associated with mixing and grinding samples, and (6) variation during analysis in the laboratory. Most variations associated with sampling, mixing, grinding, and analysis in the laboratory are known as a result of many years of study to arrive at official methods. The AVs listed below allow for the inherent variability in sources that follow the official methods, with more weight given to the areas of analytical variation. The laboratory reported value of an analyte in a sample is reviewed with respect to the guarantee using the AVs below as a guide.

Note that the AVs listed for minerals do not apply to cat and dog complete foods formulated to meet AAFCO requirements. These complete pet foods must meet AAFCO pet food profiles. All profiles have minimum mineral requirements and some have maximums as well. In this situation, the tolerances are national standards set by AAFCO but these are further adjusted by the lab to include sample variation. Current tolerances used in our lab were established in 2008.

Beginning in September 2015, we will make some adjustments to our current tolerances for complete cat and dog foods. With the implementation of a new lab software system, we will be able to set the tolerances of each product based on label moisture guarantees. Current AAFCO AVs will then be applied the profile ranges, allowing for a more equitable evaluation of the mineral content of cat and dog foods. The current system allows a wider tolerance for mineral content of wet foods than dry foods, and this will be corrected. Based on historical data, the largest impact of this change will be more violations in wet dog food for excessive calcium and phosphorus. These changes have very minimal effects on dry dog and cat foods and will not affect livestock feed or ingredients. Though the changes in mineral tolerances will need to coincide with our new lab software, we will not issue violations based on these new tolerances until January 1, 2016.

Analyte

Lower AV

Upper AV

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Analyte

Lower AV

Upper AV

Crude Protein

-3%

50%

Zinc

-40%

200%

NPN Equiv. Protein

-50%

20%

Vitamin A

-30%

200%

Crude  Fat

-20%

+5 units

Ash

 

      5%

Acid Hydrolysis  Fat

-20%

+5 units

Moisture

 

12%

Crude  Fiber

-60%

15%

Amprolium

-40%

20%

Acid Detergent Fiber

-60%

15%

Apramycin

-20%

20%

Calcium

-15%

+2 units

Bacitracin

-40%

40%

Phosphorus

-15%

+2 units

Carbadox

-20%

20%

Salt

-40%

40%

Chlortetracycline

-30%

30%

Sodium

-30%

130%

Decoquinate

-20%

20%

Magnesium

-40%

200%

Lasalocid

-25%

25%

Potassium

-30%

200%

Lincomycin

-25%

35%

Sulfur

-30%

30%

Monensin, Sodium

-30%

30%

Cobalt

-40%

200%

Oxytetracycline

-30%

30%

Copper

-40%

200%

Penicillin

-35%

35%

Iron

-40%

200%

Sulfamethazine

-20%

20%

Manganese

-40%

200%

Tylosin

-30%

30%

Molybdenum

-40%

100%

Virginiamycin

-40%

40%

Selenium

-40%

40%