Updating the CNCPS feed library with new feed amino acid profiles and efficiencies of use: Evaluation of model predictions, version 6.5.

The first version of The Cornell Net Carbohydrate and Protein System (CNCPSv1.0) was released in 1991, and was first published in 1992 and 1993 in a series of four papers (Fox et al., 1992, O'Connor et al., 1993, Russell et al., 1992, Sniffen et al., 1992). The principal objective of CNCPS was to serve as a tool for both research development and feed formulation for cattle (Russell et al., 1992). In order to fulfill these goals, the CNCPS has been continuously under development by incorporating research outcomes into mathematical equations. As a consequence, several updated versions have been released over the last 20 years (Fox et al., 2000, Fox et al., 2004, Tylutki et al., 2008). Moreover, several implementations of the program have been used by the industry to evaluate and formulate diets. Other updates to the model have included the refining of the feed library (Higgs et al., 2012a) and an improvement in the equations to predict nitrogen excretion (Higgs et al., 2012b). The latest version, CNCPSv6.1 (Tylutki et al., 2008, Van Amburgh et al., 2010), is used as a formulation and evaluation platform by AMTS.Cattle (Agricultural Modeling and Training Systems LLC; Cortland, NY), NDS (Ruminant Management & Nutrition; Reggio Emilia, Italy), DinaMilk (Fabermatica; Ostriano, Italy), and Dalex (Dalex Livestock Solutions, Los Angeles, CA).