Forage grass growth under future climate change scenarios affects fermentation and ruminant efficiency

Ergosterol and polyphenol contents as rapid indicators of orchardgrass silage safety

The ergosterol (ERG) has been proposed as a potential indicator of fungal contamination, along with polyphenol content analysis to predict silage safety. Despite efforts in controlling fungal growth in silage, mycotoxin co-contamination represents a possible risk for animal and human health. Modern analytical techniques determine a multitude of fungal metabolites contaminating feed. Nonetheless, these methods require sometimes arduous sample pre-treatment, long separation times, and expensive standard compounds to identified contaminants. Thus, the goal of this study was to suggest a rapid analysis of ERG and polyphenol contents to assess silage hygienic quality in ten orchardgrass varieties ensiled without and with biological and chemical additives. The determination of ERG on samples was performed by high-performance liquid chromatography using UV detection and UV/Vis spectrophotometry to determine the polyphenol content. Statistically significant differences (P < 0.05) between varieties, years and silage additives were found. Bepro was the unique variety that did not present ERG in the first cut in 2012. ERG content increased in the first cut in 2013 using biological additives as well as ERG and polyphenol contents in the first cut in 2013 using chemical additives compared with untreated silage. In addition, biological and chemical additives used in this study did not satisfactorily reduce the content of ERG and polyphenols in silage grass. Consequently, our results provide fast information about the progressive fungal contamination of grass silage. To our knowledge, it is the first time that the presence of ERG and polyphenols is determined in ten different orchardgrass varieties treated without and with additives. In general, ERG and polyphenol contents showed to be good indicators of orchardgrass silage safety.

Productivity and Feed Quality Performance of Napier Grass (Cenchrus purpureus) Genotypes Growing under Different Soil Moisture Levels

In the semi-arid and arid environments of Sub-Sharan Africa, forage availability throughout the year is insufficient and highly limited during the dry seasons due to limited precipitation. Thus, the identification of drought stress-tolerant forage cultivars is one of the main activities in forage development programs. In this study, Napier grass (Cenchrus purpureus), an important forage crop in Eastern and Central Africa that is broadly adapted to produce across tropical environments, was evaluated for its water use efficiency and production performance under field drought stress conditions. Eighty-four Napier grass genotypes were evaluated for their drought stress tolerance from 2018 to 2020 using agro-morphological and feed quality traits under two soil moisture stress regimes during the dry season, i.e., moderate (MWS) and severe (SWS) water stress conditions, and under rainfed conditions in the wet season (wet). Overall, the results indicated the existence of genotype variation for the traits studied. In general, the growth and productivity of the genotypes declined under SWS compared to MWS conditions. High biomass-yielding genotypes with enhanced WUE were consistently observed across harvests in each soil moisture stress regime. In addition, the top biomass-yielding genotypes produced the highest annual crude protein yield, indicating the possibility of developing high-feed-quality Napier grass genotypes for drought stress environments.