Modeling Growth of Cattle for Application within the Structure of the Cornell Net Carbohydrate and Protein System

Abstract

We use cattle around the world to convert forages, feed grains, and food byproducts into human food under production conditions that vary in soil, climate, feed composition, and genotype of cattle. Our goal over the past 20 years has been to develop a model of cattle nutrition that can be used to balance diets, thus converting these nutrients into human food as efficiently as possible. Our analyses indicate that accurate prediction of nutrient balance in each situation depends on the ability to predict cattle requirements and the supply of ruminally degraded carbohydrates, protein, microbial growth, total digestible nutrients (TDN), metabolizable energy (ME), net energy (NE), heat increment (HI), metabolizable protein (MP), net protein (NP), and essential amino acids (EAA). Formulating rations for varying cattle requirements thus requires an accounting system for the variables known to influence requirements and the dietary supply of energy and absorbed amino acids. In case studies and field experiences, we have found that the efficiency of cattle production can be improved using models to account for performance variation by accurately predicting requirements and feed utilization in individual production settings. The O‘Cornell Net Carbohydrate and Protein SystemO’ (CNCPS), as described and validated by Fox et al. (1992), Russell et al. (1992), Sniffen et al. (1992), Ainslie et al. (1993), O’Connor et al. (1993), Tylutki et al. (1994), Fox et al. (1995), the National Research Council (NRC, 1996), Pitt et al. (1996), Fox et al. (2000a, b), and Tedeschi et al. (2000 a, b), was developed for that purpose. The CNCPS has been used as a teaching tool for students and consultants as well as to design and interpret experiments, apply research results, develop tables of nutrient requirements for any cattle type and production level, and evaluate and improve feeding programs on farms.