Características fermentativas e higiênico-sanitárias de silagem de ração total contendo feno de capim- buffel e palma forrageira.

Abstract

In the Brazilian semiarid region, forage cactus represents one of the main feed alternatives for livestock due to its adaptation to low water availability and high nutritional value. When offered in troughs, this practice requires attention to management, since direct contact with animal feces can favor contamination and compromise feed quality. This study aimed to evaluate the fermentative and microbiological parameters of total mixed ration (TMR) silages based on forage cactus, associated with two proportions of buffel grass hay (7.5% and 45% dry matter basis), with or without fecal contamination, during two aerobic exposure times (0 and 24 h). The experiment was conducted at the Forage Laboratory of the Center for Agricultural Sciences (CCA) of the Federal University of Paraíba (UFPB), Campus II, in Areia, Paraíba, Brazil. A completely randomized design was used, in a 2 × 2 × 2 factorial scheme, with four replications. Analyses were performed for microbial populations of Enterobacteria and Escherichia coli, as well as for pH, water-soluble carbohydrates (WSC), and ammoniacal nitrogen relative to total nitrogen (N-NH3). The silages were exposed to a controlled environment at 30 °C for 24 h, with samples collected at 0 and 24 h.The results showed that the inclusion of buffel grass hay promoted pH balance, reduced protein degradation, and improved nitrogen conservation, enhancing the fermentative profile. A triple

interaction was observed among fiber × contamination × time for WSC (P = 0.035) and N- NH3 (P = 0.032), indicating that fermentative dynamics depend on the combination of these

factors. Increasing fiber content reduced proteolysis and N-NH3 accumulation, whereas contamination raised WSC levels, especially after 24 hours of exposure. The pH was affected by fiber (P < 0.001) and contamination (P = 0.024), showing lower values in silages with 7.5% fiber and higher cactus content, and higher values with 45% hay inclusion. Fecal contamination increased the risk of undesirable microbial growth without improving fermentation, compromising the hygienic-sanitary quality of the material. It is concluded that the association between forage cactus and buffel grass hay represents an efficient and sustainable alternative to enhance the fermentative process and ensure greater microbiological safety in total mixed ration silages, contributing to the productive stability of livestock systems in the Brazilian semiarid region.