Nutritional characteristics of cattle forage plants in the eutrophic nature reserve Oostvaardersplassen, Netherlands.

Abstract

During 1982-88 the nutritional value of the main cattle forage plants in the terrestrial part of the eutrophic wetland, the Oostvaardersplassen (dominated by Phragmites australis and Cirsium arvense, with small amounts of Urtica dioica, Poa trivialis and Salix spp.) was studied. Cattle diets were dominated by grass in early summer and autumn, P. australis in July and Aug., and browse in winter. DOM content and the chemical composition of the forage classes grasses, reed, forbs and browse varied seasonally. The DOM content of all forage classes decreased from spring to winter. However, the assumed minimum energy content for cattle maintenance (about 450 g DOM/kg DM) was reached at different moments in the different forage classes. Reed reached it in autumn, grasses in winter, forbs (living parts) remained the entire year above this level and browse remained the entire year below this level. Grazing delayed the maturation of P. trivialis, P. australis and U. dioica. The protein, K, Ca, P, Cu content of the 4 forage classes exceeded the cattle maintenance levels for these nutrients the whole year. The Na and Mg content of grasses, reed and browse were marginal in some periods of the year. Due to their high mineral contents, the forbs were an important mineral source in cattle diets. When compared with data from oligotrophic and mesotrophic habitats, the Poa-Phragmites eutrophic habitat offered comparable feed quality in spring, summer and autumn, but was inferior in winter. (Abstract retrieved from CAB Abstracts by CABI’s permission)