Proximate/Weende Analysis

DEFINITION

• The partitioning of compounds in a feed into six categories/fractions based on the chemical properties of the compounds, i.e. moisture, ash, crude protein (or Kjeldahl protein), crude lipid, crude fibre and nitrogen-free extracts (digestible carbohydrates). This quantitative analysis method of different feed macronutrients was developed in 1860 by Henneberg and Stohmann in Germany.
• This analysis was an attempt to duplicate animal digestion. After extracting the fat, the sample is subjected to an acid digestion, simulating the acid present in the stomach, followed by an alkaline digestion, simulating the alkaline environment in the small intestine. The crude fiber remaining after digestion is the portion of the sample assumed not digestible by monogastric animals. In the proximate analysis of feedstuffs, Kjeldahl nitrogen, ether extract, crude fiber and ash are determined chemically. The determination of nitrogen allows the calculation of the protein content of the sample, thus Kjeldahl protein.

DIAGRAM
FRACTIONS:

• Moisture
• Ash
• Crude protein
• Crude lipid
• Crude fibre
• Nitrogen-free extracts (digestible carbohydrates)
• Van Soest Detergent Fiber analysis

Definition

Diagram

It is important to remember that proximate analysis is not a nutrient analysis, rather it is a partitioning of both nutrients and non-nutirents into categories based on common chemical properties.

Categories

Thus, the consecutive steps of the proximate analysis are the determination of::

• moisture
• ash
• crude protein
• crude lipid
• crude fibre
• nitrogen-free extracts (digestible carbohydrates)

Due to the unsatisfactory principle, most laboratories have phased out the CF term and replaced it with the Van Soest Detergent Fiber analysis.

Proximate analysis and detergent fiber analysis are still the most widely used feed analysis methods, although some other methods are available: for non-ruminants, individual amino acid value is more important than the total protein, consequently, AMINO ACID ANALYZER and HPLC are used to do just that. individual mineral is more important than the ash value, ATOMIC ABSORPTION SPECTROPHOTOMETER is most widely used for this purpose. energy content of the feed use BOMB CALORIMETER.

Utilization of pasture and forages by ruminants: A historical perspective

Pastures, forages, and grasslands dominate the landscape across the United States and support a large ruminant population that supplies the nation with value-added animal products. A historical perspective is presented of the innovations as they occurred in the Journal of Animal Science over the past 100 yr in pasture and forage research. Consideration was given to both animal and pasture perspectives. Areas given consideration from the animal perspective were schemes for feedstuff analysis, experimental design and statistics, forage sample preservation, indirect methods of measuring intake and digestion, TDN and energy, nutritive value, harvested forage, and innovations in the grazing environment. Areas given consideration from the forage perspective were a framework for forage-animal interface research, determining pasture yield, choice of stocking method, grazing management, partitioning of forage DM, near-infrared reflectance spectroscopy technology, antiquality constituents, and forage sample preservation. Finally, the importance was discussed of applying research results from the forage-animal interface to general ruminant nutrition research beyond the interface that is focused on altered diets.

Extraction of Polyphenols from Browses

Weigh ................. of dried ....................... plant material and place in a glass beaker of approximately ............................... capacity. To it is added .......................... ml of ................................ and the beaker is suspended in .......................... and subjected to ........................... treatment for .......................... at ................. temperature. Teh contents of the beaker are then transfered to centrifuge tubes and subjected to centrifugation for ................... and approximately ................... 3000 g at 4oC.

Advantages and Limitations of Near Infrared Reflectance Analysis over Proximate Analysis

Ste-by-Step Calculation of ADF

Step-by-Step Calculation of NDF

To determine the NDF, you weigh ................... g of sample into a ..................... and seal with .................... The sealed sample is put into ....................... and ........................ solution is added for digestion in the fibre analyser.

Fractions of Proximate Analysis

Components and Procedures for: Moisture, Ash, Crude Protein, Nitrogen-Free Extract etc.

Sampling Procedure for Grains