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A. R. Son, B. G. Kim, 0994 Evaluation and development of the prediction equation for the gross energy in feed ingredients, Journal of Animal Science, Volume 94, Issue suppl_5, October 2016, Pages 476–477, https://doi.org/10.2527/jam2016-0994
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Abstract
The objective of this study was to evaluate the accuracy of a previously published equation and to develop novel prediction equations for the GE concentration in feed ingredients. Data from 297 corn, 550 corn gluten feed, 148 copra expellers, 222 copra meal, 486 palm kernel expellers, 102 rapeseed meal, and 130 soybean meal samples were used. The mean values of the feed ingredients were 10.4 ± 2.4%, 19.8 ± 9.6%, 4.44 ± 2.71%, 5.19 ± 2.17%, and 4230 ± 265 kcal/kg on an as-is basis for the moisture, CP, ether extract, ash, and GE concentrations, respectively. The predicted GE concentration of each ingredient was calculated using the published equation based on the chemical composition. To test the accuracy of the predicted GE concentrations, the regression analysis of the determined minus predicted GE concentration against the predicted GE concentration was conducted, which was able to verify the bias in the predicted values. The correlation and multiple regression procedures of SAS were used to generate the novel prediction equations. According to the results of regression analysis for the accuracy of the published equation, the intercept (−230.3; SE = 4.8 and P < 0.01) and slope (0.062; SE = 0.031 and P < 0.05) was different from 0. The recommendable regression equations for the GE concentration (kcal/kg on an as-is basis) in the feed ingredients were: Eq. 1 = 4598– (51.6 × moisture) + (37.7 × ether extract) with root mean square error = 181, R2 = 0.537, and P < 0.001; Eq. 2 = 4537– (54.2 × moisture) + (11.0 × CP) + (46.5 × ether extract)– (32.6 × ash) with root mean square error = 166, R2 = 0.612, and P < 0.001. All independent variables are in % on an as-is basis. In conclusion, the previously published equation may overestimate the GE concentrations in the feed ingredients used in this study. On the basis of the novel prediction equations, the moisture and ether extract concentrations can be good independent variables to estimate the GE concentration in the feed ingredients.
