Comparison between linear and nonlinear systems of feed formulation for broilers

Abstract

Two experiments were simultaneously carried out to compare feed formulation models: a linear model for minimum cost with a nonlinear model for maximum profitability for one-to 42-d-old broilers. One-dold male or female Cobb 500 broilers (n=2368) were allocated to one of the two trials according to sex. The experiments were performed simultaneously in an experimental poultry farm. Two housing densities were used: high density (HDH), with 14 birds/m 2 , and low density (LDH), with 10 birds/m 2 . The following treatments were evaluated: linear feed formulation and LDH (LF10); nonlinear formulation and LDH (NF10); linear formulation and HDH (LF14); and nonlinear formulation and HDH (NF14). A completely randomized design with four treatments of eight replicates each was applied. Performance and cost per kg of poultry were evaluated. Both formulation systems promoted similar broiler performance. However, the high-density feed using linear formulation reduced body weight in 42-d-old males, but not when nonlinear formulation was used. The NF10 treatment yielded the worst feed conversion ratio (p<0.05) and the lowest cost/kg broiler (p<0.05) for both sexes. The results demonstrate that the nutritional program that yields the best performance is not always the most economical one.

Performance and Egg Quality of Commercial Laying Hens Fed Diets Formulated Using Non-Linear Programming

“…The lower feed intake and higher egg mass observed in the Models treatment resulted in improved feed conversion ratio. However, optimal feed conversion ratio does not necessarily mean lower production costs (Dadalt et al, 2015). The Favorable treatment resulted in worse feed conversion compared with the Models treatment, but generated higher profit.…”

“…The results of the present study are consistent with those of Afrouziyeh et al (2010) and Afrouziyeh et al (2011), who obtained higher profitability with using non-linear programming to formulate diets for laying hens of 24 to 32 weeks of age and 32 to 44 weeks of age, respectively. In broilers, other authors (Heydari, 2014;Dadalt et al, 2015;Gonçalves et al, 2015), evaluating feed formulation for maximum profit, also observed that the better live performance provided by minimum cost feeds does not generate maximum profitability of the production system. This is due to the greater nutritional level flexibility provided by non-linear programming, which establishes the required nutritional levels to obtain the highest profit according to the economic scenario (Guevara, 2004;Eits et al, 2005).Therefore, feed formulation using non-linear programming may be an alternative method to minimum cost feed formulation due to the program's ability to combine principles of precision nutrition (Cerrate & Waldroup, 2009;Gonçalves et al, 2015).…”

“…Gonçalves et al (2015) employed mathematical models considering dietary metabolizable energy level, and broiler sex and age to formulate feeds using non-linear programming to maximize profit as a function of market scenarios. Dadalt et al (2015) conducted an experiment comparing feeds formulated using linear and non-linear programming for male and female chickens housed at densities of 10 and 14 birds/m². Their results showed that non-linear programming resulted in worse feed conversion ratio, but in higher profit.…”