Protein Determination in Feed

Protein is a critical nutrient in cattle, pig, poultry, sheep, horse and pet foods.
Although protein supplements are high in cost, they are sometimes necessary in order to meet the animal’s nutritional requirements. An adequate protein content in feed products is important for animal health and productivity, as well as for farm profitability. The protein requirements of cattle vary with age, size, and expected performance.
During lactation, larger cattle typically require more pounds of crude protein per day than smaller animals, but as a lower percentage of their total dry matter intake. In other words, lighter cattle require higher quality feeds and forages at lower quantities compared with heavier cattle. Cattle requirements for crude protein rise with increasing lactation and rate of gain. Protein is required for milk production and reproductive tract reconditioning after calving.
 

The Dumas method starts with a combustion furnace (CF) to burn the sample, obtaining elemental compounds.
Water is removed by a first physical trap (WT1 - DriStep™), placed after the combustion, and a second chemical one (WT2). Between the two, the elemental substances pass through a reduction furnace (RF). The auto-regenerative CO2 adsorbers (CO2) let pass only the elemental nitrogen that is detected by the LoGas™ innovative Thermal Conductivity Detector (TCD) with no requirement for a reference gas. The NDA 701 is controlled via PC through the intuitive DUMASoft™.

Conclusion
The obtained results are reliable and in accordance with the expected value.
The combustion method, relying on the Dumas principle, for the determination of total nitrogen in different typeskind of feeds, has been included as an official alternative to the Kjeldahl method. Results have been obtained with the following calibration curve: in a range of 0 - 9 mg N with 5 measurements of EDTA standard (%N = 9,57) (Code A00000149).
Benefits of Dumas combustion method are:

• High productivity, non-stop performance
• Time saving, few minutes required
• Moderate running costs
• Totally unsupervised, fully automated
• Omission of harsh and toxic chemicals
• Eco-friendly, low amount of residues and wastes

Several organizations working with standardization and recommendation of chemical methods have approved combustion methods for the determination of nitrogen.
Thanks to development in sophisticated instrumentation, the Dumas principle, became a practical and popular alternative for the determination of nitrogen in organic matrices.