Abstract

REZENDE, P.L.P. et al. Validation of mathematical models for prediction of voluntary consumption and weight gain of beef cattle. Arch. zootec. [online]. 2011, vol.60, n.232, pp.921-930. ISSN 1885-4494.  https://dx.doi.org/10.4321/S0004-05922011000400009.

We evaluated the use of equations of the Cornell Net Carbohydrate and Protein System (CNCPS) and National Research Council (NRC) level 1 to predict the dry matter intake and daily weight gain in tropical conditions of feedlot. We used 23 crossbred steers Holstein / Zebu kept in individual stalls with a mean age of 20 months and 260 kg live weight at the start of the experiment. The experimental diets were isonitrogenous composed of two levels of energy intake with 50 or 80% of concentrate in dry matter basis for treatments medium (TM) and high (TA), respectively. Observed variable responses between the observed and predicted values for dry matter intake and weight gain depending on level of concentrate. The best estimate of dry matter intake occurred for the treatment of middle level of concentrate on which the regression equations presented R²= 0.61 and 0.63 for the CNCPS and NRC, respectively. The models were inefficient for predicting dry matter intake in the treatment of high concentrate inclusion and did not present accurate prediction of daily weight gain in any experimental conditions analyzed.

Keywords : CNCPS; NRC; Feedlot; Requirements.

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