Composição físico-química de silagens oriundas de sistema Santa Fé produzidas em condições de sequeiro no Semiárido Nordestino brasileiro

Abstract

Producing quality fodder in adequate amounts is still a challenge in the dry conditions in the Brazilian semi-arid. Thus, the aim of this study was to evaluate the physico-chemical composition and fermentation profile of corn silages harvested at different grain maturation stages, intercropped with grasses under dry conditions. Three types of silages were produced: corn silage from a monoculture (corn silage), corn silage from a consortium with buffel grass (corn silage + buffel grass) and corn silage from a consortium with massai grass (corn silage + massai grass), at three harvesting times, defined by grain maturity stage (milky, soft farinaceous and hard farinaceous), with three replicates (mini-silos made of PVC), totaling 27 experimental units. pH levels remained between 3.8 and 4.2, considered as standard for good quality silages. The lowest gas production occurred in the corn silage + buffel grass (17.55%) at the hard farinaceous stage. Lower effluent losses occurred in the corn silage + buffel grass at the soft farinaceous stage (4.04 k/t) and in the hard farinaceous stage (4.58 k/t). The highest levels of lactic acid were observed in the corn (6.62%) and maize + buffel grass (6.10%) silages. Acetic acid contents remained high, above 2.5% in the corn and intercropped corn silages in the milky and farinaceous stages. No differences between silages for butyric acid contentes were observed. Adequate dry matter contents for good quality silages (28-30%) were obtained in the single maize silage (30.34%) and silages consorted with buffel (30.82%) and massai (28.95%) grasses in the soft farinaceous stage. The highest crude protein levels were observed in the single corn (10.69%) and corn + buffel grass (11.37%) silages. Higher levels (P <0.05) of fibrous components were observed at the milky stage for all silages. The highest in vitro dry matter digestibility level was verified in the corn silage + buffel grass (54.06%) and, the lowest, in silages in the milky stage (49.28%). The corn silages were classified as good to excellent quality. Single corn silages should be applied in the soft farinaceous stage. When in a consortium condition, the indication is of application alongside buffel grass in the soft farinaceous grain stage.