Mathematical models to predict energetic values of corn for pigs

Abstract

Aiming to determine the chemical composition and energetic values of four varieties of corn for pigs and evaluate mathematical models to predict its energetic values, twenty crossbred barrows were used, distributed in a randomized blocks design with four treatments plus the reference ration and four replicates per treatment. The corn cultivars replaced 30% of the reference ration. The chemical composition of the corn cultivars was determined. The dry matter (DM), mineral matter (MM), crude protein (CP), ether extract (EE), neutral detergent fiber (NDF), acid detergent fiber (ADF), hemicellulose (Hemi), calcium (Ca) and phosphorus (P) ranged from 86.29 to 89.04; 1.12 to 1.99; 8.13 to 8.38, 0.61 to 2.33, 12.39 to 16.70; 4.42 to 5.35, 7.04 to 11.51; 0.027 to 0.043 and 0.214 to 0.359%, respectively. The values of gross energy (GE), digestible energy (DE) and metabolizable energy (ME) ranged from 3,829 to 4,016; 3,397 to 3,522 and 3,280 to 3,383kcal/kg, respectively, and the digestibility and metabolizability coefficients of gross energy ranged from 87.42 to 89.37 and 84.01 to 86.00%. The ME:DE ratio ranged between 0.96 and 0.97. Four predictive equations were used to estimate the values of DE and none of those was adjusted. Nine predictive equations such as used to determine ME, where ME = 1.000DE - 0.68CP (R2 = 0.99) and ME = 0.997DE - 0.68CP + 0.23EE (R2 = 0.99) tha had a good adjustment, presenting significant Spearman correlation.