90 Evaluating the Difference between Formulated Dietary net Energy Values and net Energy Values Determined from Growth Performance and Estimates of Shrunk Body Weight Gain in Finishing Beef Cattle

Abstract The California Net Energy System (CNES) was developed more than 50 yr ago and partitions energy into NEm NEg, both of which can be calculated for feedstuffs as a cubic function dietary ME. Recovered (i.e., NEg) from requirements, dry matter intake (DMI), shrunk body weight gain (SWG). Thus, if composition reliably estimated relative to maturity, SWG DMI used calculate performance-adjusted net values using quadratic solution. Likewise, predicted 13.91 × RE0.9116 x EQSBW-0.6837. Evaluating observed vs. NEm, enables nutritionists better understand differences in maintenance efficiency use, associative or antagonistic effects feedstuffs, nutrient deficiencies, environmental factors. Our objective use feedlot performance carcass data numerous pens cattle fed at two locations identify potential weaknesses the CNES equations by evaluating factors affecting residuals between NEg based on NASEM (2016) tabular values. With adjustments address beef industry changes, will continue maintain functionality practical production.