Nutritive value of maize and soybean silages at different ratio in a subtropical climate condition

Abstract

Climatic conditions cause variation in the availability and nutritional quality of forages; therefore, the use of corn ( Zea mays L.) silage has been proposed. However, this crop has a low protein concentration, so the combination with legumes can improve this characteristic. The objective of this study was to evaluate the nutritive value of silage in different proportions of soybean ( Glycine max (L.) Merr.) and corn forage grown in a subtropical region. In Tamaulipas, Mexico, six treatments were evaluated: Soybean 100\% (S100), corn 100\% (C100), and soybean-corn proportions (80\%-20\%: S80C20; 60\%-40\%: S60C40; 40\%-60\%: S40C60, and 20\%-80\%: S20C80). The variables that were evaluated were: Density, pH, crude protein (CP), neutral detergent fiber (NDF), acid detergent fiber (ADF), lignin, non-fibrous carbohydrates (NFC), starch, crude fat, net energy for lactation (NEL), net energy for weight gain (NEG), and metabolizable energy (ME) and mineral content. Data were analyzed as a completely randomized design with three replicates per treatment. Treatment S100 showed the highest values (p < 0.05) in CP, ADF, crude fat, NEL, and NEG. The C100 had the highest values (p < 0.05) in starch and NFC, and the lowest pH value (p < 0.05). Meanwhile, the S40C60, S60C40, S20C80 combinations showed the highest values (p < 0.05) of TDN, ENL, and ENG. In the case of the combinations, the one with the best values was S40C60. In this regard, the mean values were: CP 143 g kg (-1) ; NEL 1.43 Mcal kg (-1) ; and pH 3.9. According to these values, it is classified as a silage of good nutritional quality, and we recommend its use in subtropical climates.