CNCPS is an abbreviation for Cornell Net Carbohydrate and Protein System, and refers to a diet evaluation and design program for dairy cattle developed by Cornell University.Since the first version was released in 1991, version 6.55 was released in 2015 and continues to the present (see figure below, courtesy of Dr. Raffrenato from RU.M.&N. sas).
Theoretical work on version 7 was completed in 2014 (Higgs, 2014) and has been partially incorporated into NDS.
As the name suggests, Carbohydrate and Protein System, this program mainly evaluates carbohydrates and proteins. Metabolic energy and protein are the main factors (first limiting factors) that affect milk yield, and an algorithm (calculation method) based on research results is incorporated, making it the most widely used program.
The program features unique analysis methods not found in other feed evaluation and design programs, such as carbohydrate digestibility, carbohydrate and protein fractionation, undigested portion measurement, and fiber-bound nitrogen measurement. (Daniel et al., 2020). This enables highly accurate feed evaluation and design.
In addition, the function to accurately predict the actual situation (model calibration) has been improved with each version. In the evaluation stage, it becomes easier to find points for improvement, and in the design stage, it is possible to design without using safety factors that lead to overpayment (Figure below, calibration screen on NDS).
The diagram below shows the overall picture of CNCPS (provided by Dr. Raffrenato from RU.M.&N. sas).
The dotted line Before CNCPS shows the input part such as feed analysis, and the After CNCPS shows the output part such as metabolizable nutrients. From this figure, you can understand that CNCPS is a program that calculates based on input information and calculates output.
Of the feed-related input items, NDF, CP, Kd of NDF,
and the Kd of starch (lower figure, Higgs et al., 2015).
That is, their values can greatly affect the goodness of fit between the model and the measurements, and may need correction if the values are not reasonable.
Similarly, cow input information, such as weight, can also affect output.
There is no program that can grasp the actual measurement 100%, so it is necessary to understand the characteristics of CNCPS well, check and correct the input, and evaluate the output.
