Metabolic Profiling of Heathland Plants in the Diet of Sheep

Little is known about how plant biochemistry influences the grazing behaviour of animals grazing heterogeneous vegetation communities. Furthermore, most biochemical profiles of grassland species are restricted to major nutritional characteristics. Recent developments in analytical techniques have made possible the detailed analysis of minor components, which can potentially affect animal feeding preferences, performance and health. Gas chromatography/time of flight mass spectroscopy (GC/TOF-MS) coupled with automated library annotation is ideally suited to the acquisition of detailed metabolite profiles of plant extracts (Wagner et al., 2003) and can be applied to other matrices such as blood and faeces. In this study GC/TOF-MS was used to identify metabolites within heathland plants, and to investigate which of these metabolites were present and absent within plasma and faeces from sheep consuming mixtures of these plants

The Impact of Using Alternative Forages on the Nutrient Value within Slurry and Its Implications for Forage Productivity in Agricultural Systems

Alternative forages can be used to provide valuable home-grown feed for ruminant livestock. Utilising these different forages could affect the manure value and the implications of incorporating these forages into farming systems, needs to be better understood. An experiment tested the hypothesis that applying slurries from ruminants, fed ensiled red clover (Trifolium pratense), lucerne (Medicago sativa) or kale (Brassica oleracea) would improve the yield of hybrid ryegrass (Lolium hybridicum), compared with applying slurries from ruminants fed ensiled hybrid ryegrass, or applying inorganic N alone. Slurries from sheep offered one of four silages were applied to ryegrass plots (at 35 t ha⁻¹) with 100 kg N ha⁻¹ inorganic fertiliser; dry matter (DM) yield was compared to plots only receiving ammonium nitrate at rates of 0, 100 and 250 kg N ha⁻¹ year-1. The DM yield of plots treated with 250 kg N, lucerne or red clover slurry was significantly higher than other treatments (Pred clover (81 kg) >kale (44 kg) >ryegrass (26 kg ha⁻¹ yr⁻¹). These FNE values represent relative efficiencies of 22% (ryegrass), 52% (kale), 47% (red clover) and 60% for lucerne slurry, with the ryegrass slurry efficiency being lowest (P = 0.005). Soil magnesium levels in plots treated with legume slurry were higher than other treatments (P<0.001). Overall, slurries from ruminants fed alternative ensiled forages increased soil nutrient status, forage productivity and better N efficiency than slurries from ruminants fed ryegrass silage. The efficiency of fertiliser use is one of the major factors influencing the sustainability of farming systems, these findings highlight the cascade in benefits from feeding ruminants alternative forages, and the need to ensure their value is effectively captured to reduce environmental risks