Evaluation of dry matter intake and daily weight gain predictions of the Cornell Net Carbohydrate and Protein System with local breeds of beef cattle in China

Evaluation of dry matter intake, average daily gain and faecal nitrogen excretion predicted by the Cornell Net Carbohydrate and Protein System with different beef cattle breeds fed in China

“…ADG was calculated dividing the difference between final and initial liveweight by the number of days of the experiment. The final shrunk body weight (SBW) was assumed as 550 kg, 410 kg, 310 kg, 320 kg and 330 kg for LIM, SIM, LX, QC and JN, respectively, and the expected body fat composition was set at 250 g·kg -1 (Table 3), which should represent an average level of body weight and target body fat in the current beef finishing system in China (Zhao et al, 2008).…”

“…As described in Molina et al (2004) and Zhao et al (2008), model predictions were evaluated for accuracy (the closeness to which a prediction approaches the experimentally determined value) and precision (repeatability of predictions) by comparing predicted to observed data. The mean bias, the mean square prediction error (MSPE) (Tedeschi, 2006), and the statistical measures of model performance (Mitchell and Sheehy, 1997) were calculated as described by Tedeschi et al (2000).…”

“…In this study, we evaluated the coincidence of DMI and ADG values predicted by CNCPSv6 and observed in five breeds of growing bulls kept on typical feed resources in Northern China. The CNCPS-predicted DMI and ADG values were based on available information, such as animal source, weather conditions, dietary nutrient density, feed available energy level, and others (Zhao et al, 2008). The actual DMI and ADG values of each animal were measured and calculated individually, and then pooled to be expressed as an average per breed (Zhao et al, 2008).…”

“…According to the criteria described by Zhao et al (2008), ideal linear regression equations for comparing the predicted and observed DMI and ADG need to meet three criteria: 1. high R 2 value (> 0.75 as a reference), 2. intercept close to (not different from) zero, and 3. slope close to 1. In this study, the R 2 values of regressions between observed and predicted DMI and ADG were high (0.94 and 0.92, respectively) and the intercept and slope were not statistically different from 0 or 1, respectively.…”

“…Zhao et al (2008) and Du et al (2010) reported that it was acceptable to predict DMI and ADG of Chinese local beef cattle using the CNCPSv5 model. No carbohydrate and protein fractions based on the CNCPS model of feeds were actually determined in their reports, however.…”