Background: Crude ash is categorized as an empirical method playing an important role in the nutritional interpretation of animal feeds, allowing indirect estimation of total organic matter (OM). Objective: Our objective was to evaluate variations in laboratory procedures for crude ash quantification regarding physical parameters (i.e., time, temperature) and ashing aids and their influences on crude ash, repeatability, and discrimination power among feeds. Methods: The “control” method was based on a simple ignition time of 3 h at 550°C. The variations are briefly described: increasing ashing time to 6 h; increasing temperature to 600°C; and using two 3 h ignition cycles at 550°C with ashing aids inclusion between them: fresh air supply, fresh air supply plus distilled water, and fresh air supply plus hydrogen peroxide. A color evaluation was also performed using a colorimetric technique. Twenty-four study materials from eight different feed types were evaluated. Results: The crude ash results differed among the method variations, but a consistent decrease in the estimates was observed when liquid aids were applied, which also improved repeatability. Ash residues did not present a consistent color pattern among methods, but the residues were darker when the control method was applied. Conclusion: The method of obtaining ash residues in animal feeds based on 550°C × 3 h does not have enough robustness and may overestimate crude ash in some feeds. Adjustments in either ignition time or temperature might improve crude ash test results, but the best test results are obtained using liquid ashing aids between two ignition cycles. Highlights: The recommended method is based on the use of 550°C and two 3 h ignition cycles with water added to the ash residue between cycles.

The influence of mixing alfalfa with whole-plant corn in different proportions on the fermentation characteristics and bacterial community of silage was investigated. Alfalfa and whole-plant corn, harvested at dry matter content of 276.47 and 328.43 g/kg fresh weight, accordingly, were chopped to approximately 2 cm and mixed at ratios of 100:0 (C0, control), 80:20 (C20), 60:40 (C40), 40:60 (C60), 20:80 (C80) and 0:100 (C100) on a fresh weight basis, respectively. Silos of each treatment were produced in triplicate and anaerobically fermented in darkness for 100 days at room temperature (20–21 °C). At silo opening, silage fermentation characteristics and bacterial composition and diversity were analyzed. The C0 silage was weakly preserved, evidenced by a low lactic acid concentration and a high value of pH, acetic acid, propionic acid, butyric acid and ammonia nitrogen. With corn proportion in the mixture increasing from 0% to 40%, silage pH, acetic acid, butyric acid and ammonia nitrogen level decreased, whereas the value of lactic acid and lactic acid to acetic acid ratio increased. The C40, C60, C80 and C100 silages’ Flieg score, used to evaluate the overall fermentation quality, was above 80 and higher than C0 (25) and C20 (61) silages. The C0 silage contained a complex bacterial community at the genus level, consisting mainly of Enterococcus (38.86%), Enterobacteria (20.61%), Rhizobium (8.45%), Lactobacillus (8.15%), Methylobacterium (5.54%) and Weissella (5.24%). As corn percentage increased from 0% to 40%, the relative abundance of desirable Lactobacillus increased and undesirable Rhizobium and Methylobacterium population reduced. With corn proportion in the mixture increasing from 0% to 40%, inclusion of corn to alfalfa at ensiling significantly improved silage fermentation quality and shifted the bacterial community for better silage preservation. Overall, high quality silage was produced when alfalfa was combined with at least 40% whole-plant corn on a fresh weight basis.

Mycotoxin incidence in forage may heavily affect the amount of toxins consumed by cattle. However, many studies have focused on mycotoxin occurrence in cereals and there are less studies of forages, particularly of grass silages. For determining the occurrence of mycotoxins in farm silages under Northern European conditions in Finland, 37 grass silage and 6 whole-crop cereal silage batches were analysed separately for surface, core and, if present, visibly mouldy spots. Mycotoxins were found in 92% of the samples. All mouldy samples contained mycotoxins. Beauvericin was the most common mycotoxin in grass silages and roquefortine C in whole-crop cereal silages. In mouldy samples, beauvericin, mycophenolic acid and roquefortine C were the most common mycotoxins in the grass silage and mycophenolic acid in the whole-crop cereal silage. Aflatoxins were not found in any of the samples. On average, all samples contained more than one type of mycotoxin. Concentrations of mycotoxins varied considerably from very low to very high values. The results of this survey indicate that silage-fed ruminants can be exposed to a broad range of mycotoxins. The absence of visible moulds does not always indicate mycotoxin-free feed. All moulded samples contained mycotoxins and some at very high concentrations, and they contained more different types of mycotoxins than samples without visible mould. Thus, feeding mouldy feeds to animals should be avoided.

New technologies related to the identification of bacterial communities in fresh forage and silage may give valuable detailed information on the best practices to produce animal feeds. The objective was to evaluate how management conditions during silage making manipulate the profile of bacterial communities and fermentation quality of grass silages. Silages were prepared from mixed timothy and meadow fescue grass using two compaction levels. As an additional treatment the grass was contaminated with soil and feces prior to tight compaction. Four additive treatments with different modes of action were applied: control without additive, formic acid-based additive, homofermentative lactic acid bacteria and salt-based additive. After 93 days the silos were opened, samples were taken and routinely analyzed. DNA extraction was carried out and PCR amplification of the bacterial 16S rRNA gene V4 region was performed using universal primers. The silage pH was higher for loose than tight compaction and higher for non-contaminated than for contaminated silages. Great shift was observed in bacterial profiles from fresh material towards silage. Lactobacillus genus was barely found on the relative abundance of fresh grass but became predominant in the final silage along with Sphingomonas genus. Use of additives improved fermentation quality and modified the bacterial profiles of grass ensiled under different management conditions.