Chemical composition, ensiling characteristics, and apparent digestibilityof summer annual forages in a subtropical double-cropping system with annual ryegrass

A 2-yr study was conducted to determine the chemical composition and digest ibility of silages made from forage sorghum, pearl millet, and tropical cor n managed to optimize forage quality. Silages were ensiled in upright concr ete silos lined with plastic and fed to heifers to determine in vivo appare nt digestibility. Samples were collected before and after ensiling to deter mine ensiling characteristics and forage quality. After ensiling, tropical corn had the greatest dry matter (DM), the lowest crude protein, and the gr eatest water-soluble concentrations. Tropical corn silage had a pH of 3.96. The pH of forage sorghum silage was 4.09, and pearl millet had a pH of 4.5 0. Pearl millet had the lowest concentration of preensiled water-soluble ca rbohydrate, which likely caused the high pH in the silage. There were no di fferences among the forages in DM loss during ensiling in yr 2. Heifers fed pearl millet silage consumed more DM, but digestible DM intake was not dif ferent among the three groups of heifers. The results of this experiment in dicate that pearl millet would be less desirable as a crop intended solely for silage production. Both forage sorghum and tropical corn could be grown specifically for ensiling based on DM digestibility. The decision on which crop to use should be based on factors such as production costs, forage yi elds, and local growing conditions rather than silage quality.