Seasonal variations in nutritive and botanical composition properties of multispecies grazing swards over an entire dairy grazing season

Background: Recently, there has been increasing interest in the use of multispecies (MS) swards in dairy grazing systems. Methods: A plot grazing study was established to investigate the potential contribution of different sward species (perennial ryegrass, legumes and herbs) sown in grazing pastures. Ten sward mixtures were sown, ranging in complexity from a perennial ryegrass (PRG) monoculture to binary mixtures including either forage legumes or herbs to a five-species mixture; four different nitrogen (N) application rates of 0, 100, 150 and 200 kg N ha⁻¹ were applied to each sward. Results: Species abundance for all sward species components was associated with the interaction of time point and sward mixture; species abundance for all sward components, except PRG, was associated with the interaction of N application and sward mixture. The interactions of time point and sward mixture, and time point and N application rate, were associated with all analysed sward chemical components, except for sward digestibility. Conclusions: Increased N application rates reduced the level of clover in all sward mixtures. Increased levels of white clover led to increased sward crude protein levels; the inclusion of ribwort plantain led to some seasonal variation in the nutritive value of swards.