Effects of water-soluble carbohydrates from grasses on the nutrition of grazing ruminants.

Grasses used for grazing, particularly modern ryegrass varieties and other C3 grasses, show high variability in water-soluble carbohydrate (WSC) concentrations (5%-40% of DM) depending on species and varieties, environment, and management. High WSC concentrations, typical of high-latitude regions, have recently also been reported under Mediterranean conditions. In ruminants, pasture WSC may be positively associated with grazing time, DMI, animal performance, and pasture nutrient use efficiency. However, along with other nutritional factors, they can also be associated with rapid ruminal fermentation and low rumen pH, which may negatively affect milk fat synthesis under certain grazing conditions.