Grasslands which have been actively managed for a long time and which in modern times have not been subject to cultivation such as fertilization are called semi-natural grasslands. These rare and species-rich areas hold an ecological, biological and historical value and if the management stops these areas will likely diminish. More effective agricultural systems and a declining number of grazing animals have in Sweden, among other countries, made semi-natural grasslands less valuable as foraging areas. Shrubs and fast growing plants rapidly colonize abandoned semi-natural grasslands, threatening biodiversity. The objective of this experiment was to determine the effects of breed and season on diet composition, with special reference to four competitive species found in wet areas ? in cattle grazing heterogeneous semi-natural grasslands ? and thereby contribute to improved management of these areas.