Determination of Moisture in Feed Products

Significance of the Topic

Determining moisture in animal feed is critical for ensuring product safety, quality, and consistency. Accurate moisture measurement influences feed texture, taste, microbial stability, and supports calculations of purity, yield, and nutrient analysis on a dry basis.

Objectives and Study Overview

This application note evaluates the performance of the LECO TGM800 thermogravimetric analyzer for moisture determination in a range of feed materials. The study compares fixed drying time and mass constancy drying approaches using standard AOAC 930.15 parameters. Feed types analyzed include distillers grain, corn silage, corn grain, and hay.

Methodology and Instrumentation

The TGM800 measures sample mass loss as temperature increases under controlled atmosphere and ventilation. Key method steps:

• Sample preparation: grind feed to pass a 1.0 mm screen, weigh ~1.0–2.0 g into aluminum foil crucibles.
• Temperature program: ramp from 25 °C to 135 °C at 10 °C/min, hold for 120 min (fixed time) or until mass constancy (0 min hold, 9 min constancy window, 0.001 g level).
• Gas flow: 4 L/min.
• Instruments and accessories: TGM800 analyzer, aluminum foil crucibles (1.5″ and 2.4″), carousels, scoops.
• Method reference: AOAC Official Method 930.15 Moisture in Animal Feed.

Main Results and Discussion

Both fixed drying time and mass constancy methods produced consistent moisture values with low standard deviations across feed types:

• Distillers grain: ~12.8–12.9% moisture (s ≤ 0.05).
• Corn silage: ~4.1–4.2% moisture (s ≤ 0.12).
• Corn grain: ~2.2% moisture (s ≤ 0.08).
• Hay: ~3.3–3.4% moisture (s ≤ 0.11).

Results demonstrate the TGM800’s precision and repeatability. A higher ramp rate (20 °C/min) may shorten analysis time without compromising accuracy.

Benefits and Practical Applications

Key advantages of this method include:

• High accuracy and repeatability for diverse feed matrices.
• Compliance with established AOAC standards.
• Flexible analysis time options (fixed or mass constancy drying).
• Minimal sample handling and straightforward operation.

This approach supports quality control in feed production, regulatory compliance, and research studies.

Future Trends and Possibilities

Emerging opportunities to enhance moisture analysis include:

• Integration of faster temperature ramps and advanced control algorithms.
• Coupling thermogravimetry with evolved gas analysis (e.g., FTIR, MS) for compositional insights.
• Automation and in-line moisture monitoring in production environments.
• Utilizing machine learning for predictive moisture profiling and method optimization.

Conclusion

The LECO TGM800 thermogravimetric analyzer provides a robust, reliable method for moisture determination in feed products. Both fixed drying time and mass constancy approaches yield precise results that meet AOAC standards, making the technique suitable for routine QA/QC and research applications.

References

• AOAC Official Method 930.15: Moisture in Animal Feed.
• LECO Corporation. Application Note: Determination of Moisture in Feed Products, TGM800, Rev 2 (2019).