Abstract
The effects of the heavy application of dairy cattle slurry to timothy grass (Phleum pratense L.) on the yield and nutrient content of the grass; residual nitrate levels in soil, and the voluntary intake, milk production and blood chemical components of dairy cattle fed on the silage of this grass were estimated. It was shown that the heavy application of dairy cattle slurry adversely affects grass productivity (decrease in yield and deterioration of botanical composition), grass quality (increase in potassium and crude protein content, decrease in magnesium content), the health status of dairy cattle (decrease in magnesium content of blood, and increase in the urea-N content of blood), and environmental influences (increase in soil nitrate levels). These influences were caused by the input of excess amount of nutrients inherent in the heavy application of slurry. In order to avoid these negative effects, it is important to apply the appropriate amount of slurry according to the fertilizer recommendation, Hokkaido.
