Evaluation Of Energetics Systems For Dairy Cows

The objective was evaluate accuracy and precision of the estimated energy requirements for lactating dairy of the Oliveira (2015) system to tropical condition, compared to AFRC (1993), NRC (2001), Feed into Milk (THOMAS, 2004), INRA (2007), CSIRO (2007) and proposed by Moraes et al. (2015). Four rotative feeding trials were used as dataset, totalizing 181 observations of total digestible nutrient (TDN) intake from 16 diets. Dataset had wide variation in animal performance (milk yield between 6.1 to 36.5 kg/day), diet and TDN intake (4.0 to 16.6 kg/day). The Oliveira (2015) system explained 83% of the observed TDN intake, over-predicted TDN intake by 0.34 kg/day and presented root mean square error of prediction (RMSPE) of the 12.2% of the observed TDN intake. AFRC (1993), NRC (2001), Feed into Milk (THOMAS, 2014) e Moraes et al (2015) systems had similar RMSPE (P > 0.05) to Oliveira (2015) system, indicating similar accuracy to predict energy requirement for dairy cows under tropical conditions. We recommended to investigate the adequacy these systems in long term feeding trials.