Challenges in measuring moisture content of feeds.

Area of Science:

• Animal Science
• Analytical Chemistry
• Food Science

Background:

• Accurate determination of moisture (water) content in feed is critical for the feed industry.
• Empirical methods, primarily loss on drying (oven drying), are widely used but introduce bias.
• This bias impacts confidence in moisture values and the accurate quantification of other nutrients.

Purpose of the Study:

• To review moisture determination methods in feedstuffs.
• To compare different methods across various feed matrices.
• To recommend a reference method and improve moisture testing practices.

Main Methods:

• Review of empirical methods (loss on drying) and direct methods (Karl Fischer titration).
• Comparison of moisture determination results across diverse feed ingredients and mixed feeds.
• Evaluation of method validation and applicability to different feed matrices.

Main Results:

• Empirical methods exhibit significant bias and vary in effectiveness.
• Methods validated for one feed type may not be suitable for others without revalidation.
• Karl Fischer titration serves as a suitable reference method for evaluating empirical techniques.

Conclusions:

• There is a clear need to evaluate and standardize moisture testing methods in feed laboratories.
• Empirical methods should be reported as 'loss on drying' with specified conditions, not 'moisture'.
• Direct methods like Karl Fischer titration are recommended as reference standards for validating empirical feed moisture analysis.