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From Weender Analysis to CNCPS
Built on the old proven and yet new
For decades, farmers, nutritionists, and scientists have been calculating feed rations for cattle based on feed analysis using the Weender analysis, or the extended Weender analysis according to Van Soest. A few years ago, American nutritionists made changes to the existing system. But why?
Weender Analysis: Where it all began
The basis for meaningful feed ration calculation is knowledge of what is contained in the individual feed components. This is achieved through feed analysis in the laboratory. In German laboratories, the Weender analysis, expanded by the examination according to Van Soest, is typically used for analysis.
The Weender analysis was established in 1860 at the agricultural research station in Weende, Göttingen. It involves fractionation into different classes.
(NFC == Nicht Faser Kohlenhydrate; NDF== Neutrale Detergentien-Faser; ADF == Saure Detergentien-Faser; ADL == Saures Detergentien-Lignin)
The Weender analysis or the extended Weender analysis can determine the components of the analyzed feed at a specific time, the time of analysis.
But what about the animal that consumes the feed? The same cattle breeds are kept worldwide under sometimes vastly different environmental conditions. There are differences in body weight, body condition, feeding management, etc. Can silages with the same chemical composition achieve the same feeding success in all animals? And what about the silages? Why do two silages with similar chemical compositions not perform equally well?
The aim of an American research group was to integrate these questions into a single system. In the 1970s, they developed the Cornell Net Carbohydrate Protein System, abbreviated as CNCPS.
What is CNCPS?
The need for a model that defines the function/effect of rumen bacteria and the requirements of the animal organism, and can assess feed requirements and make performance predictions, led to the development of CNCPS.
The model is still based on the well-established Weender analysis and the detergent analysis according to Van Soest. It was further enhanced by examining the digestion processes in the rumen.
To illustrate and evaluate the processes in the rumen (digestion, passage rate of carbohydrates, fats, and proteins), a rumen model was developed by the research group. Most nutritional models describe rumen bacteria growth as a function of total digestible nutrients or energy, but they do not consider the dynamics of bacterial growth. Therefore, a new model was developed by the American research group. They found that rumen bacteria also have a maintenance requirement. In addition, growth is dependent on carbohydrate digestion. It was found that fiber-digesting bacteria have a lower maintenance requirement and grow more slowly than non-fiber-digesting bacteria. Fiber-digesting bacteria use ammonia as their "food source," while non-fiber-digesting bacteria use peptide-N or amino acids.
In this regard, the research group emphasized the continuous integration of the latest scientific findings into the CNCPS system. This also led to a more precise fractionation of proteins and carbohydrates. Depending on the solubility of the individual protein and carbohydrate fractions, they are classified into different classes. This enables more accurate statements about the digestibility of specific feed materials:
These dynamic properties, in addition to the chemical properties of a feed material, must be considered in feeding to accurately determine the feed value of the feed materials. Chemical properties alone are not sufficient to predict the quality and resulting animal performance.
The CNCPS model considers the following parameters in addition to conventional systems:
- Feed intake
- Ruminal fermentation of protein and carbohydrates
- Digestion and absorption processes in the intestine
- Nutrient requirements for maintenance, growth, lactation, and pregnancy
- Reserves
- Nutrient excretions
Time does not stand still - CNCPS in the ration calculation program
Since the beginnings of CNCPS in the 1970s, the model has been constantly adapted to scientific innovations. Almost annually, scientifically based innovations/findings have been incorporated into the system. This allows the CNCPS system to provide even more precise results.
To make the CNCPS system easy to use for every user, it has been incorporated into a dedicated CNCPS ration calculation program. This feed calculation program calculates the optimal feed ration using the data obtained through CNCPS.
CNCPS is now used by users in over 40 countries worldwide. It has also been observed that this system provides a better approximation to the real situation (feed intake, performance parameters) by feeding consultants in Germany.