Qualidade fermentativa de silagens de milho sem espiga aditivada com palma forrageira e seu uso em dietas na terminação de ovinos

Abstract

The objective was to evaluate the effect of the inclusion of forage cactus as an additive in the preparation of corn stover silage, through the fermentation quality and performance of finishing sheep. In order to achieve the objectives, two experiments were carried out. In experiment I – levels of inclusion of forage cactus as an additive were evaluated on the fermentative profile, microbial populations, aerobic stability and chemical composition of the silages. The design was completely randomized with four treatments: 0, 10, 20 and 40% forage cactus levels in natural matter, with five replications per treatment. In experiment II – the potential of three cornstover silage added with forage cactus in diets for finishing sheep was evaluated. The experimental design was completely randomized with three treatments: 1) cornstover silage; 2) 90% cornstover silage + 10% forage cactus and 3) 80% cornstover silage + 20% cactus based on natural matter. The variables analyzed were: dry matter intake, water intake, productive performance, nutrient digestibility, ingestive behavior and feeding and rumination efficiency. With regard to experiment I, the bromatological composition of corn silage without the cob added with cactus pear levels showed a decreasing linear effect for DM (P=0.001) and EE (P=0.006) and a quadratic effect for OM (P=0.001), MM (P=0.001) and PB (P=0.002). For the fermentative effect, a quadratic effect was observed for pH (P=0.005) and CHOs (P=0.049). A quadratic effect was also observed for PG (P=0.035) and RMS (P=0.0057) and an increasing linear effect for PE (P=0.0171). Regarding the microbiological count, a decreasing linear effect was observed for BAL (P=0.030) and a quadratic effect for ML (P=0.001). The inclusion of cactus pear also resulted in an increase in aerobic stability, where the 20% level showed a stability break after 96 hours and with 40% there was no stability break after 120 hours of exposure to air. For the organic acid concentration, there was a quadratic effect for AL (P=0.001) and AA (P=0.001) and a decreasing linear effect for the AL:AA ratio (P=0.001). For experiment II, there was a significant effect for DM (P=0.0201), MO (P=0.0152), EE (P=0.0001), CNF (P=0.0007), MEC (P=0.0289) intakes. A significant effect was also observed for water intake via food (P=0.0001) and water via drinker (P=0.0019). For nutrient digestibility, only MO (P=0.0187), EE (P=0.0095), NDF (P=0.0005), CNF (P=0.0001) and EM (P=0.0001) showed a significant effect. There was a significant effect for the performance variables GPT (P=0.0148), ADG (P=0.0148), CA (P=0.0229) and EA (P=0.0137). For the ingestive behavior data, there was a significant effect for the ruminating variable (P=0.0143) and for the rumination efficiency of MS (P=0.0111) and NDF (P=0.0013). Thus, it is recommended to include 20% of forage cactus in the natural material as an additive in the silage of the corn stover plant improving its fermentative quality as well as its aerobic stability and its use in the feeding of finishing sheep does not compromise performance, in addition to reducing water intake via drinking fountain, supplying part of the animals' water needs via food, a point of extreme relevance in semi-arid regions.