Meta-analysis of corn plants, green fodder (ensilage), and silages of different types of maize hybrids used in experimental conditions in Brazil

Abstract

The objective of this study was to conduct a meta-analysis of scientific publications from January 1994 to December 2014, to evaluate the chemical composition of corn plants, green forage, and silages of three different types of maize hybrids (simple, double, and triple) used in experimental conditions in Brazil. The sub-bases Corn Cultivation and Green Fodder were composed of 49 experiments, consisting of 481 treatments, and the sub-base Silage consisted of 24 studies composed of 163 treatments, involving 478 silos. In the Corn Cultivation sub-base, the variables of spacing, plant height, grain yield, organic matter content, and total carbohydrates of maize silage differed (P < 0.05) according to the hybrid type. The number of corn plants per hectare, number of spikes per plant, and the levels of neutral detergent fiber, acid detergent fiber, hemicellulose, and lignin did not differ (P > 0.05) according to the hybrid type. In the Green Forage sub-base (ensilage), the main difference (P < 0.05) was regarding the in vitro dry matter digestibility, whereby the triple hybrids (59.38%) had lower values than the simple (73.05%) and double (72.74%) hybrids. In the Silage sub-base, the variables of organic matter, total carbohydrates, cellulose, in vitro dry matter digestibility, and pH differed (P < 0.05) according to the hybrid type. While the variables dry matter, non-fibrous carbohydrates, neutral detergent fiber, acid detergent fiber, hemicellulose, lignin, total digestible nutrients, ethereal extract, crude protein, and ammonium nitrogen did not differ (P > 0.05) according to the hybrid type. The variability in the determination of parameters, such as dry matter yield, dry matter content, and non-fibrous carbohydrates of corn silage, and the non-determination of the starch content demonstrated that the chemical compositions of Brazilian corn silage have not yet been fully clarified. The types of maize hybrids (simple, double, and/or triple) mainly differ in terms of grain production. In many situations, the silage processes are not conducted in an ideal way, and the differences as a function of the maize plants (type of hybrid) are minimized due to losses during the ensiling process.