Silicon Fertigation and Azospirillum brasilense Modulate the Microbiological Profile of Total Mixed Ration Silage for Dairy Goats

Abstract

The objective of this study was to evaluate the effects of fertigation with silicon (Si) combined with inoculation with Azospirillum brasilense during off-season corn cultivation on the fermentation profile, microbiological quality, and chemical and bromatological composition of total mixed ration (TMR) silage formulated for dairy goats. The experiment was conducted using a randomized block design in a 4 × 2 factorial layout, with five replicates. The Si rates were 0, 4, 8, and 12 kg ha−1, with and without inoculation with A. brasilense (strains Ab-V5 and Ab-V6). The fermentation profile, populations of lactic acid bacteria (LAB), molds, and yeasts, as well as the chemical and bromatological composition of the silages, were evaluated. Fertigation with Si and inoculation with A. brasilense did not significantly influence (p > 0.05) the pH, ammoniacal nitrogen, buffering capacity, losses due to gases and effluents, dry matter recovery, or the chemical and bromatological composition of the silages. There was a significant interaction (p < 0.0001) between Si rate and A. brasilense inoculation for LAB, molds, and yeasts. The highest LAB counts were observed without A. brasilense inoculation at 0 and 4 kg ha−1 Si (7.36 and 7.22 log10 CFU g−1, respectively), which did not differ statistically from each other. In the presence of A. brasilense, LAB counts remained statistically stable at 0, 4, and 8 kg ha−1 Si (6.51–6.71 log10 CFU g−1), with a marked reduction at 12 kg ha−1.